KR20240007192A - Laminates and display devices for display devices - Google Patents

Abstract

The present disclosure is a laminate for a display device having a base layer and a functional layer containing fluorine, wherein a load of 9.8 N is applied to the surface of the display device laminate on the functional layer side using an eraser with a diameter of 6 mm to 2500 A laminate for a display device is provided, wherein the absolute value of the amount of charge on the surface on the functional layer side of the laminate for a display device after performing a reciprocating rubbing eraser test is 10.0 nC or less.

Description

Laminates and display devices for display devices

This disclosure relates to a laminate for a display device and a display device using the same.

On the surface of the display device, a laminate including functional layers having various performances such as hard coat properties, scratch resistance, antireflection properties, antiglare properties, antistatic properties, and antifouling properties is disposed.

In recent years, not only smartphones and tablet terminals but also display devices such as notebook-type personal computers have a touch function. A display device with a touch function is operated by directly touching the surface with a finger or the like, so wear resistance and slipperiness are required.

Additionally, portable display devices such as smartphones and tablet terminals may be stored in, for example, pockets or bags of clothing, and may be exposed to the display device by the fabric of the clothing or bag, or other items contained within the clothing pocket or bag. In some cases, the surface may be chafed. For this reason, more wear resistance is required for portable display devices.

Recently, flexible displays such as foldable displays, rollable displays, and bendable displays have been attracting attention, and the development of laminates disposed on the surface of flexible displays is actively progressing. For example, the use of a resin substrate instead of a glass substrate is being considered. For example, in Patent Document 1, a plastic substrate having high hardness and excellent optical properties, and a hard coating layer disposed on at least one side of the plastic substrate are described. A display device window film having a display device has been proposed.

Since flexible displays are used or stored in a bent state, for example, the surface of the curved portion is likely to be chafed. For this reason, in flexible displays, excellent wear resistance is further required in the bent portion.

In order to increase wear resistance, it is known, for example, to reduce the coefficient of friction. Specifically, a technique for providing low friction by coating a fluorine-based surface treatment agent or adding a fluorine-based additive is known. For example, Patent Document 2 discloses a surface treatment agent containing a fluoroxyalkylene group-containing polymer composition that can provide a coating excellent in water and oil repellency, scratch resistance, low dynamic friction, and wear resistance.

However, when the surface of the functional layer in the above-mentioned laminate is chafed, the components contained in the functional layer are swept away or the functional layer is chafed away, which sometimes reduces the performance of the functional layer, resulting in further wear resistance. Improvement is required.

Japanese Patent Publication No. 2016-125063 Japanese Patent No. 6140348 Publication

The present disclosure has been made in light of the above-described circumstances, and its main purpose is to provide a laminate for a display device and a display device having excellent wear resistance.

In order to solve the above problems, the inventors of the present disclosure paid attention to the eraser test as an abrasion test and conducted a thorough study on the abrasion resistance of the laminate for a display device. As a result, surprisingly, they found that there is a correlation between the abrasion resistance and the absolute value of the electric charge. paid it The present disclosure is based on this knowledge.

One embodiment of the present disclosure is a laminate for a display device having a base layer and a functional layer containing fluorine, wherein the surface of the display device laminate on the functional layer side is subjected to 9.8 N using an eraser with a diameter of 6 mm. Provided is a laminate for a display device, wherein the absolute value of the amount of charge on the surface on the functional layer side of the laminate for a display device is 10.0 nC or less after performing an eraser test of 2500 reciprocal rubbings by applying a load of .

In the display device laminate according to the present disclosure, the frictional force against the eraser after the eraser test is relative to the average value of the initial frictional force against the eraser on the surface on the functional layer side of the display device laminate in the initial stage. It is desirable that the ratio of the maximum value of is 1.7 or less.

In addition, in the display device laminate according to the present disclosure, the ratio of the number of fluorine atoms to the total number of atoms of all elements on the surface on the functional layer side at the initial stage, as measured by X-ray photoelectron spectroscopy, is: It is preferable that the ratio of the number of fluorine atoms to the total number of atoms of all elements on the surface on the functional layer side after the eraser test is 0.4 or more.

Additionally, in the laminate for a display device in the present disclosure, it is preferable that the functional layer contains an antistatic agent. In this case, it is preferable that the antistatic agent is a conductive polymer.

Additionally, the display device laminate in the present disclosure may have an impact absorption layer on the side of the base layer opposite to the functional layer or between the base layer and the functional layer.

Additionally, the laminate for a display device in the present disclosure may have an adhesive layer for sticking on the side of the base material layer opposite to the functional layer.

Another embodiment of the present disclosure provides a display device including a display panel and the above-described display device laminate disposed on an observer side of the display panel.

The present disclosure has the effect of providing a laminate for a display device and a display device having excellent wear resistance.

1 is a schematic cross-sectional view illustrating a laminate for a display device according to the present disclosure.
Figure 2 is a schematic diagram explaining a method of measuring frictional force on an eraser.
Figure 3 is a schematic diagram explaining a dynamic bending test.
4 is a schematic cross-sectional view illustrating a laminate for a display device in the present disclosure.
5 is a schematic cross-sectional view illustrating a laminate for a display device according to the present disclosure.
6 is a schematic cross-sectional view illustrating a laminate for a display device according to the present disclosure.
7 is a schematic cross-sectional view illustrating a display device in the present disclosure.

Below, embodiments of the present disclosure will be described with reference to the drawings and the like. However, the present disclosure can be implemented in many different aspects, and should not be construed as being limited to the description of the embodiments illustrated below. In addition, in order to make the explanation clearer, the drawings may schematically express the width, thickness, shape, etc. of each part compared to the actual form, but are only examples and do not limit the interpretation of the present disclosure. . In addition, in this specification and each drawing, elements similar to those described above with respect to the existing drawings are given the same reference numerals, and detailed descriptions may be omitted as appropriate.

In this specification, when expressing the mode of arranging another member on top of another member, when simply expressed as “above” or “below”, unless otherwise specified, it means that, unless otherwise specified, it is placed in contact with a certain member, directly above, or immediately above. This includes both the case of arranging another member below and the case of arranging another member above or below a certain member with another member interposed. In addition, in this specification, when expressing the mode of arranging another member on the surface of a certain member, when simply expressed as “on the surface side” or “on the surface,” unless otherwise specified, so that it is in contact with a certain member, This includes both the case of arranging another member directly above or immediately below, and the case of arranging another member above or below a certain member with another member interposed.

The inventors of the present disclosure paid attention to the eraser test as an abrasion test, conducted intensive studies on the abrasion resistance of the display device laminate, and obtained the following findings.

The inventors of the present disclosure performed an eraser test on a laminate for a display device and measured the friction force before and after the eraser test and the amount of charge after the eraser test. When the absolute value of the amount of charge after the eraser test was relatively small, the change in friction force before and after the eraser test was We found that it tends to be relatively small. In other words, it was found that there was a correlation between wear resistance and the absolute value of the electric charge after the eraser test. In addition, the relationship between wear resistance and the absolute value of the charge after the eraser test was investigated in detail, and it was found that in order to provide excellent wear resistance, it is important to keep the absolute value of the charge after the eraser test below a predetermined value.

Hereinafter, the laminate for a display device and the display device in the present disclosure will be described in detail.

A. Laminate for display device

The laminate for a display device in the present disclosure is a laminate for a display device having a base layer and a functional layer containing fluorine, and the surface of the laminate for a display device on the functional layer side is rubbed with an eraser having a diameter of 6 mm. After performing an eraser test of 2500 reciprocations by applying a load of 9.8 N, the absolute value of the electric charge on the surface of the display device laminate on the functional layer side is 10.0 nC or less.

1 is a schematic cross-sectional view showing an example of a laminate for a display device in the present disclosure. As shown in FIG. 1, the laminate 1 for a display device has a base material layer 2 and a functional layer 3. Additionally, the absolute value of the electric charge on the surface of the display device laminate 1 on the functional layer 3 side after the predetermined eraser test becomes less than or equal to the predetermined value.

As described above, the present disclosure is made based on the new finding that, in a laminate for a display device, there is a correlation between wear resistance and the absolute value of the electric charge after an eraser test. In the present disclosure, excellent wear resistance can be obtained when the absolute value of the electric charge on the surface of the display device laminate after the eraser test on the functional layer side is below a predetermined value.

The reason for this is not clear, but is guessed as follows. That is, when an eraser test is performed on the surface of a display device laminate, the surface of the display device laminate is charged due to friction caused by the eraser. In general, since the surface of the layer containing fluorine tends to be negatively charged, the functional layer containing fluorine is likely to be negatively charged, and the surface on the functional layer side of the display device laminate is affected by friction caused by the eraser. is negatively charged. Due to this effect, the contact surface of the eraser with the surface on the functional layer side of the display device laminate becomes positively charged. At this time, when the electrostatic force increases by performing the eraser test, that is, when the absolute value of the electric charge after the eraser test increases, the attractive force increases, so it is thought that the fluorine contained in the functional layer is detached and becomes more likely to adhere to the eraser. If the fluorine contained in the functional layer is desorbed, the effect of fluorine on wear resistance is reduced. On the other hand, when the electrostatic force is small even when the erase test is performed, that is, when the absolute value of the charge after the erase test is small, the attractive force is small, so it is thought that the fluorine contained in the functional layer is unlikely to be separated. In this case, the effect of wear resistance due to fluorine can be maintained. Therefore, in the present disclosure, the absolute value of the amount of charge on the surface on the functional layer side of the display device laminate after the eraser test is less than or equal to a predetermined value, so that the surface on the functional layer side of the display device laminate after the eraser test is It is thought that electrification can be suppressed and desorption of fluorine by the eraser test as described above can be suppressed.

As a result, it is assumed that excellent wear resistance can be obtained.

In addition, the friction caused by an eraser is close to the friction caused by a touch pen, and the eraser test can evaluate the wear resistance against relatively soft objects such as a touch pen, fingers, and cloth of clothes or bags. In the present disclosure, since the absolute value of the electric charge on the surface of the functional layer side of the display device laminate after the eraser test is below a predetermined value, it can be applied to relatively soft objects such as touch pens, fingers, and cloth of clothes or bags, for example. In contrast, excellent wear resistance can be obtained.

Hereinafter, each configuration of the display device laminate in the present disclosure will be described.

1. Characteristics of laminates for display devices

In the present disclosure, the surface of the functional layer side of the display device laminate is subjected to an eraser test in which a load of 9.8 N is applied using an eraser with a diameter of 6 mm and the surface of the display device laminate is rubbed 2500 times. The absolute value of the electric charge on the surface is 10.0 nC or less, preferably 8 nC or less, and more preferably 6 nC or less. When the absolute value of the electric charge is within the above range, excellent wear resistance can be obtained. In addition, the smaller the absolute value of the electric charge, the more preferable it is, and may be, for example, 0nc.

Here, the eraser test can be performed by the following method. That is, using an eraser with a diameter of 6 mm, insert it into a jig with a hole with a diameter of 6 mm so that the tip of the eraser is exposed by 4 mm, and install this eraser attachment jig in a Hakjin type friction tester, with a load of 9.8 N and a moving speed of 80 mm/sec. , Under the condition of a moving distance of 40 mm, the surface on the functional layer side of the display device laminate is rubbed 2500 times with an eraser. As an eraser with a diameter of 6 mm, for example, an eraser with a diameter of ϕ6 mm manufactured by Minoan can be used. In addition, as a Gakjin type friction tester, for example, Hakjin type friction fastness tester AB-301 manufactured by Tester Sangyo can be used.

Additionally, the amount of electric charge can be measured by the following method. First, using a glass plate as a test stand, an ionizer is applied to the glass plate for 1 minute to eliminate static electricity. In addition, the display device laminate was cut to a size of 20 mm x 80 mm (including the eraser test section 6 mm x 40 mm) to produce a test piece, and an ionizer was applied to both sides of the test piece for more than 30 seconds and less than 60 seconds to eliminate static electricity.

Next, the end of the test piece is fixed on a glass plate with cellophane tape, and the eraser test is performed. Next, the test piece after the eraser test is set on a Faraday gauge, the temperature condition is set to 23 ± 5°C, and the humidity condition is set to 40 ± 10% RH, and the amount of charge is measured.

At this time, using insulating and non-magnetic tweezers, the eraser-untested portion (end of the sample) is picked up and the test piece after the eraser test is lifted. In addition, after the test piece after the eraser test is lifted, the amount of charge is measured without touching it to another fixed surface. The measurement of electric charge is performed within 3 minutes after the eraser test. In addition, the measurement point of the electric charge amount is the entire sample size.

As a Faraday gauge, for example, Faraday cage "KQ-1400" manufactured by Kasuga Denki Co., Ltd. can be used. Additionally, as an ionizer, for example, a fan-type ionizer “KD-750B” manufactured by Gasga Denki Co., Ltd. can be used. In addition, as the tweezers, for example, ESD (electrostatic protection) tweezers “P-643-S” manufactured by Kenneth Inc. can be used.

Methods for adjusting the absolute value of the electric charge on the functional layer side of the display device laminate after the eraser test include, for example, a method for adjusting the surface hardness of the functional layer, a method for adjusting the thickness of the functional layer, and a display device. Method of adjusting the concentration of fluorine on the functional layer side of the laminate, method of adjusting the content of the antistatic agent, method of adjusting the position of the layer containing the antistatic agent, and adjusting the drying temperature when forming the functional layer. How to do it, etc.

For example, as the surface hardness of the functional layer increases, the absolute value of the electric charge tends to decrease. In addition, for example, as the thickness of the functional layer becomes thinner, the surface hardness of the functional layer tends to decrease and the absolute value of the above charge tends to increase; on the other hand, as the thickness of the functional layer increases, the surface hardness of the functional layer increases, and the The absolute value of the charge tends to decrease. In addition, for example, as the fluorine concentration on the functional layer side of the display device laminate increases, slipperiness improves and the absolute value of the electric charge tends to decrease, while the display device laminate tends to have a lower fluorine concentration. As the concentration of fluorine on the surface on the functional layer side decreases, slipperiness decreases and the absolute value of the electric charge tends to increase.

In addition, for example, as the content of the antistatic agent increases, the absolute value of the electric charge tends to decrease. However, if the content of the antistatic agent increases excessively, the surface hardness of the functional layer decreases, and the absolute value of the electric charge decreases. On the other hand, as the content of the antistatic agent decreases, the surface hardness of the functional layer increases and the absolute value of the electric charge tends to decrease.

In addition, for example, as the distance between the surface on which the eraser test is performed and the layer containing the antistatic agent becomes closer, the absolute value of the electric charge tends to decrease, while on the other hand, the surface on which the eraser test is performed and the layer containing the antistatic agent tend to decrease. As the distance between increases, the absolute value of the electric charge tends to increase.

In the present disclosure, the distance between the surface on which the eraser test is performed and the layer containing the antistatic agent is preferably 10 μm or less, particularly preferably 6 μm or less, and especially preferably 4 μm or less.

Here, “the distance between the surface on which the eraser test is performed and the layer containing the antistatic agent” refers to the following distances.

In other words, “the surface on which the eraser test is performed” refers to the outermost surface on the functional layer side of the display device laminate. In addition, “the layer containing an antistatic agent” refers to the layer that first contains an antistatic agent when viewed from the outermost surface side to the base layer side. That is, if the outermost surface layer contains an antistatic agent, the outermost layer is a layer containing an antistatic agent. If the outermost surface layer does not contain an antistatic layer and the next layer contains an antistatic agent, then the outermost layer is a layer containing an antistatic agent. , the next layer becomes “a layer containing an antistatic agent.”

“The distance between the surface where the eraser test is performed and the layer containing the antistatic agent” refers to the distance from the outermost surface to the surface on the outermost surface side of the “layer containing the antistatic agent.”

Additionally, for example, as the drying temperature during formation of the functional layer decreases, the absolute value of the above charge tends to decrease, and on the other hand, as the drying temperature during formation of the functional layer increases, the antistatic agent tends to migrate to the surface of the functional layer. This becomes difficult, and the absolute value of the amount of charge tends to increase.

In addition, in the present disclosure, when a steel wool test is performed in which the surface on the functional layer side of the display device laminate is rubbed 2500 times by applying a predetermined load using #0000 steel wool, the function of the display device laminate is determined. The maximum load at which no damage is observed on the surface of the layer side is, for example, preferably 4.9 N or more, more preferably 9.8 N or more, and even more preferably 14.7 N or more. When the maximum load is within the above range, the hardness of the surface on the functional layer side of the display device laminate can be increased and scratch resistance can be improved.

Here, the steel wool test can be performed by the following method. That is, using #0000 steel wool, the steel wool is fixed to a jig of 2 cm Rub it. As #0000 steel wool, Bonestar #0000 manufactured by Nippon Steel Wool Company can be used. In addition, as a testing machine, for example, Gakjin type friction fastness tester AB-301 manufactured by Tester Sangyo can be used. In addition, the steel wool test is performed, for example, by bonding a protective film having an adhesive layer on one side of a PET substrate to the side of the substrate layer side of a laminate for a display device with a size of 4 cm x 10 cm, and then attaching the display device to a tester. This is carried out in a state where the surface on the functional layer side of the laminate for a display device is placed on the outside, and the end of the laminate for a display device is fixed with a cellophane tape.

Additionally, the steel wool test can be used to evaluate abrasion resistance against relatively hard objects, such as pockets in clothing or items contained in a bag.

In addition, in the present disclosure, the pencil hardness of the surface on the functional layer side of the display device laminate is preferably, for example, H or higher, more preferably 2H or higher, and even more preferably 3H or higher. When the pencil hardness is within the above range, the hardness of the surface on the functional layer side of the display device laminate can be increased and scratch resistance can be improved.

Here, pencil hardness is measured by the pencil hardness test specified in JIS K5600-5-4 (1999). Specifically, using the test pencil specified in JIS-S-6006, a pencil hardness test specified in JIS K5600-5-4 (1999) was performed on the surface on the functional layer side of the display device laminate to determine whether there were any scratches. This can be done by evaluating the highest pencil hardness that does not occur. Measurement conditions include an angle of 45°, load (1000 g), speed of 0.5 mm/sec or more and 1 mm/sec or less, and temperature of 23 ± 2°C. As a pencil hardness tester, for example, a pencil scratching coating film hardness tester manufactured by Toyo Seiki Co., Ltd. can be used.

In addition, in the present disclosure, the average value of the frictional force against the eraser on the functional layer side of the display device laminate is preferably, for example, 0.98 N or more and 9.80 N or less, and more preferably 1.96 N or more and 8.80 N or less. It is preferable, and it is more preferable that it is 2.45N or more and 7.80N or less. If the average value of the initial frictional force against the eraser is within the above range, wear resistance can be increased.

In addition, in the present disclosure, the functional layer side of the display device laminate is subjected to an eraser test in which a load of 9.8 N is applied using an eraser with a diameter of 6 mm and the surface of the display device laminate is rubbed 2500 times. In terms of the maximum value of friction against the eraser, for example, it is preferably 0.98N or more and 9.80N or less, more preferably 1.96N or more and 8.80N or less, and even more preferably 2.45N or more and 7.80N or less. When the frictional force against the eraser after the above eraser test is within the above range, excellent wear resistance can be obtained and excellent antistatic properties can be maintained.

In addition, the ratio of the maximum value of the frictional force against the eraser after the eraser test to the average value of the initial frictional force against the eraser on the surface of the functional layer side of the display device laminate is preferably 1.7 or less, for example, 1.5. It is more preferable that it is 1.3 or less, and it is still more preferable that it is 1.3 or less. When the ratio of friction force to the eraser is within the above range, wear resistance can be improved. Additionally, the smaller the ratio of friction force to the eraser, the more preferable it is, and may be, for example, 1.00.

The ratio of the frictional force against the eraser is A, the average value of the frictional force against the eraser on the surface on the functional layer side of the initial display device laminate before the eraser test, and A on the functional layer side surface of the display device laminate after the eraser test. When the maximum value of friction against the eraser is B, it is obtained by the following equation.

Ratio of friction force = B/A

Here, the frictional force against the eraser is determined by using an eraser with a diameter of 6 mm, inserting it into a jig with a hole with a diameter of 6 mm so that the tip of the eraser is exposed by 4 mm, installing this eraser attachment jig in a friction measuring machine, and determining a load of 1.96 N and movement. Measurement can be made by rubbing the surface on the functional layer side of the display device laminate with an eraser at a speed of 840 mm/min. As an eraser with a diameter of 6 mm, for example, an eraser with a diameter of ϕ6 mm manufactured by Minoan can be used. Additionally, as a friction measuring device, for example, TRIBOGEAR TYPE18 manufactured by Shinto Chemical Co., Ltd. can be used. Specifically, as shown in FIG. 2, first, the above-described eraser test is performed on a part of the surface 30 on the functional layer side of the display device laminate 1, and the eraser test implementation section 32 of a rectangular shape is ) to form. Next, using an eraser, the surface 30 on the functional layer side of the display device laminate 1 is divided into an erase test non-performed portion 31, an erase test performed portion 32, and an erase test portion, as indicated by arrows. The friction force is measured by rubbing in the order of the unimplemented portion 31. At that time, the eraser is moved perpendicularly to the longitudinal direction of the rectangular eraser test implementation section 32, as indicated by the arrow. The average value of the frictional force against the eraser in the part where the eraser test was not performed can be taken as the average value of the initial frictional force against the eraser, and the maximum value of the frictional force against the eraser in the eraser test conducted part can be the maximum value of the frictional force against the eraser after the eraser test. In addition, as shown in FIG. 2, the average value of the initial frictional force against the eraser is in the eraser test non-implementation part 31 when the point at which the frictional force against the eraser of the eraser test performing part 32 is the maximum value is set to 0 mm. In this case, the average value of the friction force in the range of 4.2 mm to 9.8 mm is taken based on the above point of 0 mm.

In addition, in the present disclosure, the ratio of the number of fluorine atoms to the total number of atoms of all elements on the surface of the functional layer side of the display device laminate as measured by X-ray photoelectron spectroscopy is, for example, 7 at%. It is preferable that it is 60 at% or less, more preferably 20 at% or more and 50 at% or less, and even more preferably 25 at% or more and 45 at% or less. If the ratio of the initial number of fluorine atoms is within the above range, wear resistance can be increased.

In addition, in the present disclosure, the surface on the functional layer side of the display device laminate is subjected to an eraser test in which a load of 9.8 N is applied using an eraser with a diameter of 6 mm and the surface is rubbed for 2,500 reciprocations, and then measured by X-ray photoelectron spectroscopy. The ratio of the number of fluorine atoms to the total number of atoms of all elements on the functional layer side of the display device laminate is preferably, for example, 7 at% or more and 60 at% or less, and more preferably 20 at% or more and 50 at% or less. It is preferable, and it is more preferable that it is 25 at% or more and 45 at% or less. If the ratio of the number of fluorine atoms after the eraser test is within the above range, desorption of fluorine contained in the functional layer by the eraser test can be suppressed, and wear resistance can be improved.

In addition, the ratio of the number of fluorine atoms to the total number of atoms of all elements on the surface of the functional layer side of the initial display device laminate as measured by X-ray photoelectron spectroscopy, the display device laminate after the eraser test. The ratio of the number of fluorine atoms to the total number of atoms of all elements on the functional layer side of the sieve is, for example, preferably 0.4 or more, more preferably 0.6 or more, and still more preferably 0.7 or more. When the ratio of the number of fluorine atoms is within the above range, wear resistance can be improved. In addition, the larger the ratio of the number of fluorine atoms, the more preferable it is, and may be, for example, 1.0.

The ratio of the ratio of the number of fluorine atoms is C, the ratio of the number of fluorine atoms to the total number of atoms of all elements on the surface of the functional layer side of the initial display device laminate before the eraser test, C, and the display after the eraser test. When D is the ratio of the number of fluorine atoms to the total number of atoms of all elements on the functional layer side of the device laminate, it is obtained by the following equation.

Ratio of the number of fluorine atoms = D/C

Additionally, in the present disclosure, it is preferable that the ratio of the number of atoms of fluorine to the total number of atoms of all elements on the surface of the eraser, as measured by X-ray photoelectron spectroscopy, is, for example, below the detection limit.

In addition, in the present disclosure, the surface on the functional layer side of the display device laminate is subjected to an eraser test in which a load of 9.8 N is applied using an eraser with a diameter of 6 mm and the surface is rubbed for 2,500 reciprocations, and then measured by X-ray photoelectron spectroscopy. The ratio of the number of fluorine atoms to the total number of atoms of all elements on the surface in contact with the surface on the functional layer side of the display device laminate of the eraser is preferably, for example, 15 at% or less, and more preferably 10 at% or less. And, it is more preferable that it is 5 at% or less. If the ratio of the number of fluorine atoms on the contact surface of the eraser after the eraser test is within the above range, the desorption of fluorine contained in the functional layer during the eraser test can be prevented from adhering to the eraser, and the wear resistance can be improved. there is.

Here, the ratio of the number of fluorine atoms to the total number of atoms of all elements is the ratio of the number of fluorine atoms to the total number of atoms of all elements present on the sample surface, as measured by X-ray photoelectron spectroscopy (XPS). , specifically, refers to the fluorine atom number ratio (at%) when the total number of carbon atoms, oxygen atoms, fluorine atoms, nitrogen atoms, silicon atoms, calcium atoms, and chlorine atoms is 100 at%.

The ratio of the number of fluorine atoms to the total number of atoms of all elements can be determined by analyzing the composition of the sample surface by X-ray photoelectron spectroscopy (XPS). Specifically, it can be obtained by the following procedure. First, using an X-ray photoelectron spectrometer, X-rays are irradiated in the depth direction from the sample surface under the following conditions to measure the As an X-ray photoelectron spectrometer, for example, AXIS-NOVA manufactured by Kratos can be used. When measuring the ratio of the number of fluorine atoms to the total number of atoms of all elements, C, O, F, N, Si, Ca, and Cl are used as elements to be analyzed, and the background determined by the Shirley method is calculated from the obtained spectrum. Subtracted from the area of the peak, using the relative sensitivity coefficient method, the number of fluorine atoms when the total number of carbon atoms, oxygen atoms, fluorine atoms, nitrogen atoms, silicon atoms, calcium atoms, and chlorine atoms is 100 at%. The ratio (at%) can be obtained.

<Measurement conditions>

· Incident X-ray: Monochromated Al-Kα ray (monochromatized X-ray, Hv=1486.6eV)

· X-ray irradiation area (measurement area): 110㎛ϕ

· X-ray output: 150W (15kV·6.7mA)

· Photoelectron introduction angle; 90°±15° (sample normal is 0°)

· Charge neutralization conditions: electron neutralizing gun (+6V, 0.05mA), low-acceleration Ar ⁺ ion irradiation

· Measured peaks: C1s, O1s, F1s, N1s, Si2p, Ca2p, Cl2p

In addition, the ratio of the number of fluorine atoms to the total number of atoms of all elements on the surface of the functional layer side of the initial display device laminate and the total elements on the functional layer side of the display device laminate after the eraser test. In the case of measuring the ratio of the number of fluorine atoms to the total number of atoms, for example, as described above, an eraser test implementation section 32 as shown in FIG. 2 is formed, and an eraser test non-performance section 31 is formed. The ratio of the number of fluorine atoms to the total number of atoms of all elements in the initial ratio is the ratio of the number of fluorine atoms to the total number of atoms of all elements in the eraser test implementation unit 32. The ratio of the number of fluorine atoms may be the ratio of the number of atoms of fluorine to the total number of atoms of all elements after the eraser test.

The laminate for a display device in the present disclosure preferably has a total light transmittance of, for example, 85% or more, more preferably 88% or more, and even more preferably 90% or more. As the total light transmittance is high in this way, a laminate for a display device with good transparency can be obtained.

Here, the total light transmittance of the laminate for a display device can be measured based on JIS K7361-1, and can be measured, for example, with a haze meter HM150 manufactured by Murakami Shikisai Kijutsu Kenkyujo.

The haze of the display device laminate in the present disclosure is preferably, for example, 5% or less, more preferably 2% or less, and still more preferably 1% or less. By having a low haze in this way, a laminate for a display device with good transparency can be obtained.

Here, the haze of the display device laminate can be measured based on JIS K-7136, and can be measured, for example, with a haze meter HM150 manufactured by Murakami Shikisai Kijutsu Kenkyujo.

The laminate for a display device in the present disclosure preferably has bending resistance. Specifically, when the dynamic bending test described below is performed on the display device laminate, it is preferable that no cracks or fractures occur in the display device laminate.

The dynamic bending test is performed as follows. First, prepare a laminate for a display device with a size of 20 mm x 100 mm. In the dynamic bending test, as shown in FIG. 3(a), the short edge 1C of the display device laminate 1 and the short edge 1D opposite the short edge 1C are, Each is fixed with fixing parts 51 arranged in parallel. Additionally, as shown in Fig. 3(a), the fixing portion 51 is capable of sliding in the horizontal direction. Next, as shown in FIG. 3(b), the display device laminate 1 is deformed to be folded by moving the fixing portions 51 closer to each other, and as shown in FIG. 3(c). Likewise, after moving the fixing part 51 to a position where the spacing d between the two opposing short sides 1C and 1D fixed by the fixing part 51 of the display device laminate 1 becomes a predetermined value, , the fixing portion 51 is moved in the reverse direction to eliminate the deformation of the display device laminate 1. As shown in FIGS. 3A to 3C , the display device laminate 1 can be folded by 180° by moving the fixing portion 51. In addition, a dynamic bending test is performed to prevent the bent portion 1E of the display device laminate 1 from protruding from the lower end of the fixing portion 51, and the gap when the fixing portion 51 is closest is controlled to , the spacing d between the two opposing short sides 1C and 1D of the display device laminate 1 can be set to a predetermined value. For example, if the spacing d between the short edges 1C and 1D is 30 mm, the outer diameter of the bent portion 1E is considered to be 30 mm.

In the display device laminate, when a dynamic bending test of 180° folding is repeated 200,000 times so that the spacing d between the opposing short edges 1C and 1D of the display device laminate 1 is 30 mm, no cracks or It is preferable that no fracture occurs, and it is more preferable that no crack or fracture occurs when the process is repeated 500,000 times. Among these, it is preferable that no cracks or fractures occur when the 180° folding dynamic bending test is repeated 200,000 times so that the spacing d between the opposing short edges 1C and 1D of the display device laminate is 20 mm. It is desirable that no cracks or fractures occur when the 180° folding dynamic bending test is repeated 200,000 times so that the spacing d between the opposing short edges 1C and 1D of the display device laminate 1 is 10 mm.

In the dynamic bending test, the display device laminate may be folded so that the functional layer is on the outside, or the display device laminate may be folded so that the functional layer is on the inside, but in either case, the display device laminate may crack. Alternatively, it is desirable that no fracture occurs.

2. Functional layer

The functional layer in the present disclosure is a layer disposed on one side of the base layer and containing fluorine. By containing fluorine, the functional layer can provide wear resistance and antifouling properties to the display device laminate.

The functional layer is not particularly limited as long as it contains fluorine. The functional layer may contain, for example, a fluorine compound and a resin, or may contain a fluorine resin.

When the functional layer contains a fluorine compound and a resin, as the fluorine compound, for example, those known as a fluorine-based antifouling agent, a fluorine-based leveling agent, a fluorine-based surfactant, etc. can be used. Examples of the fluorine compound include organic fluorine compounds, and specifically, perfluoro compounds. Examples of the perfluoro compound include perfluoro compounds having a perfluoropolyether group, perfluoroalkylene group, perfluoroalkyl group, etc. The perfluoroalkyl group and the perfluoroalkyl group may be straight chain or branched chain. A fluorine compound may be used individually by 1 type, or may be used in mixture of 2 or more types.

Additionally, it is preferable that the fluorine compound is combined with the resin component. By bonding the fluorine compound to the resin component, bleed-out of the fluorine compound can be suppressed, and wear resistance and stain resistance can be maintained over a long period of time. In addition, it is easy to maintain wear resistance and stain resistance even after the eraser test.

Since the fluorine compound is preferably bonded to the resin component, a fluorine compound having a reactive functional group is preferably used. That is, the functional layer preferably contains a cured product of a resin composition containing a fluorine compound having a reactive functional group and a polymerizable compound described later. Examples of the reactive functional group include ethylenically unsaturated bonding groups such as (meth)acryloyl group, vinyl group, and allyl group, epoxy group, and oxetanyl group.

The number of reactive functional groups that the fluorine compound has may be 1 or more, and is preferably 2 or more. By using a fluorine compound having two or more reactive functional groups, scratch resistance and wear resistance can be improved.

Additionally, the fluorine compound may contain silicon. That is, the functional layer may contain fluorine and silicon. Examples of the fluorine compound containing silicon include fluorine compounds having a siloxane bond in the molecule. By using a fluorine compound having a siloxane bond, slipperiness can be improved and scratch resistance can be increased. Additionally, since slippage is improved when touched with a finger or a touch pen, the tactile feel can be improved.

The fluorine compound is preferably, for example, a fluorine compound having a reactive functional group or a fluorine compound containing a reactive functional group and silicon.

Examples of the fluorine compound having a reactive functional group include fluorine-containing monomers having an ethylenically unsaturated bond, fluorine-containing polymers or oligomers having a fluoroalkylene group in the main chain, and fluorine having a fluoroalkylene group or fluoroalkyl group in the main chain and side chains. Containing polymers or oligomers may be mentioned. For fluorine compounds having a reactive functional group, reference can be made to, for example, Japanese Patent Application Laid-Open No. 2017-19247.

Examples of the fluorine compound containing a reactive functional group and silicon include, for example, a silicon-containing vinylidene fluoride copolymer obtained by reacting a fluorine compound having the above reactive functional group with an organic silicone having a reactive functional group in the molecule.

In addition, the fluorine compound containing a reactive functional group and silicon includes, for example, a fluorine compound having a reactive functional group and a perfluoropolyether group, especially a silane unit having a reactive functional group, and a silane unit having a perfluoropolyether group. Fluorine compounds are also preferably used. For these fluorine compounds, reference may be made to International Publication No. 2012/157682, for example.

In the functional layer, the fluorine compound may exist uniformly, for example, or may be unevenly distributed on the side of the functional layer opposite to the base material layer. Among these, it is preferable that the fluorine compound is distributed on the surface of the functional layer opposite to the base material layer. Sufficient wear resistance and antifouling properties can be obtained with a small addition amount, and a decrease in the surface hardness of the functional layer can be suppressed.

As a method of localizing the fluorine compound on the side of the functional layer opposite to the base layer, for example, when the functional layer is a single layer, applying a resin composition for the functional layer on the base layer when forming the functional layer. Before drying and curing, the coating film is heated to lower the viscosity of the resin component contained in the coating film to increase fluidity, thereby localizing the fluorine compound on the side opposite to the base layer of the functional layer. By using a fluorine compound with a low surface tension, making the fluorine compound float on the surface of the coating film without applying heat when drying the coating film, and then curing the coating film, the fluorine compound is placed on the side opposite to the base layer of the functional layer. A method of distributing it on the surface can be mentioned. In addition, for example, when the functional layer is multilayered, the fluorine compound is contained in the layer located on the side opposite to the base material layer among the multilayer functional layers, so that it is placed on the side opposite to the base material layer of the functional layer. Fluorine compounds can be localized.

The content of the fluorine compound is not particularly limited as long as it can obtain a functional layer that satisfies the absolute value of the above-mentioned charge. For example, it is preferably 0.01 parts by mass or more and 15 parts by mass or less per 100 parts by mass of the resin component. . If the content of the fluorine compound is too small, there is a possibility that sufficient wear resistance and antifouling properties may not be provided to the functional layer. Additionally, if the content of the fluorine compound is too high, the surface hardness of the functional layer may decrease and wear resistance may decrease.

In addition, when the functional layer contains a fluorine compound and a resin, examples of the resin include a cured product of a polymerizable compound. The cured product of the polymerizable compound can be obtained by subjecting the polymerizable compound to a polymerization reaction by a known method, using a polymerization initiator as necessary.

A polymerizable compound has at least one polymerizable functional group in its molecule. As the polymerizable compound, for example, at least one of a radically polymerizable compound and a cationically polymerizable compound can be used.

A radically polymerizable compound is a compound having a radically polymerizable group. The radical polymerizable group possessed by the radical polymerizable compound may be any functional group capable of generating a radical polymerization reaction, and is not particularly limited, but examples include a group containing a carbon-carbon unsaturated double bond, and specifically, Examples include vinyl group and (meth)acryloyl group. In addition, when the radically polymerizable compound has two or more radically polymerizable groups, these radically polymerizable groups may be the same or different.

The number of radical polymerizable groups in one molecule of the radically polymerizable compound is preferably 2 or more, and more preferably 3 or more, since the surface hardness of the functional layer increases and the scratch resistance improves.

As a radically polymerizable compound, because of its high reactivity, compounds having a (meth)acryloyl group are preferable, for example, urethane (meth)acrylate, polyester (meth)acrylate, and epoxy (meth)acrylate. Polyfunctional (meth)acrylate with several (meth)acryloyl groups in the molecule, called polyfluoroalkyl (meth)acrylate, melamine (meth)acrylate, polyfluoroalkyl (meth)acrylate, silicone (meth)acrylate, etc., has a molecular weight of hundreds to thousands ( Meth)acrylate monomers and oligomers can be preferably used, and polyfunctional (meth)acrylate polymers having two or more (meth)acryloyl groups in the side chain of the acrylate polymer can also be preferably used. Among them, a polyfunctional (meth)acrylate monomer having two or more (meth)acryloyl groups in one molecule can be preferably used. When the functional layer contains a cured product of a polyfunctional (meth)acrylate monomer, the surface hardness of the functional layer can be increased and scratch resistance can be improved. Additionally, adhesion can be improved. Additionally, polyfunctional (meth)acrylate oligomers or polymers having two or more (meth)acryloyl groups in one molecule can also be preferably used. When the functional layer contains a cured product of a polyfunctional (meth)acrylate oligomer or polymer, the surface hardness of the functional layer can be increased and scratch resistance can be improved. It can also improve bending resistance and adhesion.

In addition, in this specification, (meth)acryloyl represents each of acryloyl and methacryloyl, and (meth)acrylate represents each of acrylate and methacrylate.

Specific examples of polyfunctional (meth)acrylate monomers include those described in Japanese Patent Application Laid-Open No. 2019-132930. Among them, it is preferable to have 3 to 6 (meth)acryloyl groups per molecule because it has high reactivity, increases the surface hardness of the functional layer, and improves scratch resistance. Examples of such polyfunctional (meth)acrylate monomers include pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), pentaerythritol tetraacrylate (PETTA), and dipentaerythritol penta. Acrylate (DPPA), trimethylolpropane tri(meth)acrylate, tripentaerythritol octa(meth)acrylate, tetrapentaerythritol deca(meth)acrylate, etc. can be preferably used. In particular, at least one selected from pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexaacrylate is preferable.

Additionally, when a radically polymerizable compound is used, scratch resistance may be reduced due to a flexible group in the molecular structure. Therefore, in order to suppress the decrease in scratch resistance caused by the flexible component (soft segment), it is preferable to use a radically polymerizable compound that does not have a flexible group introduced into the molecular structure. Specifically, it is preferable to use a radically polymerizable compound that is not modified with EO or PO. By using such a radically polymerizable compound, the crosslinking point can be increased and the scratch resistance can be improved.

The functional layer may contain a monofunctional (meth)acrylate monomer as a radically polymerizable compound in order to adjust hardness and viscosity, improve adhesion, etc. Specific examples of monofunctional (meth)acrylate monomers include those described in Japanese Patent Application Laid-Open No. 2019-132930.

A cationically polymerizable compound is a compound having a cationic polymerizable group. The cationic polymerizable group of the cationically polymerizable compound may be any functional group capable of causing a cationic polymerization reaction, and is not particularly limited, and examples include an epoxy group, oxetanyl group, and vinyl ether group. Additionally, when the cationically polymerizable compound has two or more cationic polymerizable groups, these cationic polymerizable groups may be the same or different.

The number of cationic polymerizable groups in one molecule of the cationically polymerizable compound is preferably two or more, and more preferably three or more, since the surface hardness of the functional layer increases and the scratch resistance improves.

Moreover, as the cationically polymerizable compound, a compound having at least one of an epoxy group and an oxetanyl group as a cationic polymerizable group is preferable, and a compound having two or more of at least one of an epoxy group and an oxetanyl group in one molecule is preferable. It is more desirable. Cyclic ether groups such as epoxy groups and oxetanyl groups are preferable because the shrinkage accompanying the polymerization reaction is small. In addition, compounds having an epoxy group among the cyclic ether groups have the advantage that compounds with various structures are easy to obtain, do not adversely affect the durability of the obtained functional layer, and compatibility with radically polymerizable compounds is easy to control. In addition, the oxetanyl group among the cyclic ether groups has a high degree of polymerization compared to the epoxy group and is low toxic, and when the obtained functional layer is combined with a compound having an epoxy group, the network formation rate obtained from the cationically polymerizable compound in the coating film is accelerated. , there are advantages such as forming an independent network without leaving unreacted monomers in the film even in areas where radical polymerizable compounds exist.

Cationically polymerizable compounds having an epoxy group include, for example, polyglycidyl ethers of polyhydric alcohols having an alicyclic ring, or alicyclic compounds obtained by epoxidizing a cyclohexene ring- or cyclopentene ring-containing compound with a suitable oxidizing agent such as hydrogen peroxide or peracid. family epoxy resin; Aliphatic epoxy resins such as polyglycidyl ethers of aliphatic polyhydric alcohols or their alkylene oxide adducts, polyglycidyl esters of aliphatic long-chain polybasic acids, and homopolymers and copolymers of glycidyl (meth)acrylate; Glycidyl ethers and novolacs produced by the reaction of bisphenols such as bisphenol A, bisphenol F, and hydrogenated bisphenol A, or their derivatives such as alkylene oxide adducts and caprolactone adducts, and epichlorohydrin. These include epoxy resins, and glycidyl ether type epoxy resins derived from bisphenols.

Specific examples of cycloaliphatic epoxy resins, glycidyl ether type epoxy resins, and cationic polymerizable compounds having an oxetanyl group include those described in Japanese Patent Application Laid-Open No. 2018-104682.

The functional layer may contain a polymerization initiator as needed. As the polymerization initiator, radical polymerization initiator, cationic polymerization initiator, radical and cationic polymerization initiator, etc. can be appropriately selected and used. These polymerization initiators are decomposed by at least one of light irradiation and heating to generate radicals or cations to advance radical polymerization and cationic polymerization. In addition, there are cases in which the polymerization initiator is completely decomposed and does not remain in the functional layer.

In addition, when the functional layer contains a fluororesin, examples of the fluororesin include a cured product of a polymerizable compound containing fluorine. A cured product of a fluorine-containing polymerizable compound can be obtained by subjecting a fluorine-containing polymerizable compound to a polymerization reaction by a known method, using a polymerization initiator as necessary.

A polymerizable compound containing fluorine has at least one polymerizable functional group in the molecule. As the fluorine-containing polymerizable compound, for example, at least one of a radically polymerizable compound and a cationically polymerizable compound can be used. Additionally, as the polymerizable compound containing fluorine, for example, any of fluorine-containing monomers and oligomers can be used.

Additionally, when the functional layer contains a fluorine resin, a polymerizable compound that does not contain fluorine may be used in addition to the polymerizable compound that contains fluorine. That is, the functional layer may contain a cured product of a resin composition containing a polymerizable compound containing fluorine and a polymerizable compound that does not contain fluorine. The polymerizable compound that does not contain fluorine can be the same as the polymerizable compound used when the above functional layer contains a fluorine compound and a resin.

Additionally, the functional layer preferably contains an antistatic agent. Antistatic properties can be imparted to a laminate for a display device. Additionally, by adjusting the content of the antistatic agent, the absolute value of the electric charge on the surface on the functional layer side of the display device laminate after the eraser test can be adjusted so that it falls within a predetermined range.

Examples of antistatic agents include ion conduction type antistatic agents and electron conduction type antistatic agents. Antistatic agents may be used individually, or may be used in combination of two or more types.

As an ion conduction type antistatic agent, for example, either a low molecular type antistatic agent or a high molecular type antistatic agent can be used. The polymer type antistatic agent is, for example, a product obtained by increasing the molecular weight of an ion conductive type antistatic agent and introducing a conductivity imparting functional group of the ion conductive type antistatic agent into the polymer. Examples of the ion conductive antistatic agent include cationic antistatic agents such as quaternary ammonium salts and pyridinium salts; Anionic antistatic agents such as lithium salts, sodium salts, potassium salts, etc., and alkali metal salts such as sulfonic acid, phosphoric acid, and carboxylic acid; Positive antistatic agents such as amino acid series and amino acid sulfate ester series; Nonionic antistatic agents such as amino alcohol-based, glycerin-based, and polyethylene glycol-based; Ionic liquids, etc. can be mentioned. Among these, quaternary ammonium salts and lithium salts are preferable because they exhibit excellent compatibility with resins.

Examples of the electron conductive antistatic agent include conductive polymers such as polyacetylene-based and polythiophene-based; Examples include conductive particles such as metal particles, metal oxide particles, and carbon nanotubes, and conductive fibers. Additionally, an antistatic agent that combines a dopant with a conductive polymer such as polyacetylene or polythiophene, or an antistatic agent that contains conductive particles in the conductive polymer can also be used. Among these, conductive polymers are preferable from the viewpoint of maintaining antistatic properties.

Specifically, the conductive polymer includes polyacetylene, polyaniline, polythiophene, polypyrrole, polyphenylene sulfide, poly(1,6-heptadiyne), polybiphenylene (polyparaphenylene), and polyparaffinyl. Conductive polymers such as lene sulfide, polyphenylacetylene, poly(2,5-thienylene), or derivatives thereof may be included. Preferred examples include polythiophene-based conductive polymers such as 3,4-ethylenedioxythiophene (PEDOT). By using the above-described conductive polymer as an antistatic agent, antistatic properties can be maintained over a long period of time.

Examples of the metal constituting the metal fine particles include Au, Ag, Cu, Al, Fe, Ni, Pd, and Pt alone or alloys of these metals.

The metal oxide constituting the metal oxide particle is not particularly limited and includes, for example, tin oxide, antimony oxide, antimony-doped tin oxide (ATO), tin-doped indium oxide (ITO), aluminum-doped zinc oxide (AZO), Fluorine-doped tin oxide (FTO), zinc oxide (ZnO), etc. can be mentioned. Among them, antimony-doped tin oxide (ATO) is preferable from the viewpoint of exhibiting excellent antistatic properties. Moreover, among ATO, chain-shaped ATO in which a plurality of ATO particles are connected is preferable.

Among the above antistatic agents, polymer-type antistatic agents and conductive polymers are preferable, and conductive polymers are more preferable. Polymeric antistatic agents and conductive polymers can provide antistatic properties even in small amounts and can maintain surface hardness and optical properties.

In addition, in the case where the functional layer contains an antistatic agent, and as will be described later, when the functional layer is multilayered, at least one layer among the multilayered functional layers need only contain an antistatic agent.

In this case, any layer among the multi-layered functional layers may contain an antistatic agent, but it is preferable that the layer located close to the surface opposite to the base layer contains an antistatic agent, especially the base material layer. It is preferable that the layer located on the surface opposite to the layer, that is, the outermost layer among the multilayer functional layers, contains an antistatic agent. This is because the closer the distance between the surface on which the erase test is performed and the layer containing the antistatic layer, the easier it is to adjust the absolute value of the electric charge on the surface on the functional layer side of the display device laminate after the erase test to a predetermined range.

The content of the antistatic agent is not particularly limited as long as it is an amount that can obtain a functional layer that satisfies the absolute value of the charge amount described above, and is appropriately selected depending on the type of antistatic agent, etc. For example, the content of the antistatic agent is preferably 0.1 parts by mass or more and 100 parts by mass or less, more preferably 0.2 parts by mass or more and 50 parts by mass or less, and 0.3 parts by mass or more and 20 parts by mass or less, for example, based on 100 parts by mass of the resin component. It is more desirable. If the content of the antistatic agent is too small, there is a possibility that sufficient antistatic properties may not be imparted to the functional layer. Additionally, if the content of the antistatic agent is too high, the surface hardness of the functional layer may decrease and wear resistance may decrease. In addition, when the functional layer contains an antistatic agent and, as will be described later, when the functional layer is multilayered, it is preferable that the content of the antistatic agent in the layer containing the antistatic agent among the multilayer functional layers is within the above range.

The functional layer may contain, as necessary, inorganic particles, organic particles, ultraviolet absorbers, antioxidants, light stabilizers, anti-glare agents, leveling agents, surfactants, lubricants, various sensitizers, flame retardants, adhesion agents, and polymerization inhibitors. It may contain additives such as chemicals and surface modifiers.

The functional layer may be a single layer or may be a multilayer.

The thickness of the functional layer is not particularly limited as long as it can obtain a functional layer that satisfies the above-mentioned characteristics. For example, it is preferably 0.5 μm or more and 50 μm or less, and more preferably 1.0 μm or more and 40 μm or less, It is more preferable that it is 1.5 ㎛ or more and 30 ㎛ or less. If the thickness of the functional layer is too thin, the surface hardness of the functional layer may decrease and wear resistance may decrease. Additionally, if the thickness of the functional layer is too thick, there is a risk that flexibility may be impaired. Additionally, as described above, by adjusting the thickness of the functional layer, the absolute value of the amount of charge on the surface on the functional layer side of the display device laminate after the eraser test can be adjusted to be within a predetermined range. In addition, when the functional layer is multilayered, it is preferable that the thickness of the layer located on the surface opposite to the base layer among the multilayered functional layers is within the above range.

Here, the thickness of the functional layer is an arbitrary value obtained by measuring from a cross section in the thickness direction of the display device laminate observed with a transmission electron microscope (TEM), a scanning electron microscope (SEM), or a scanning transmission electron microscope (STEM). It can be taken as the average value of the thickness of 10 locations. In addition, the same method can be used for measuring the thickness of other layers of the display device laminate.

The functional layer may be disposed on one side of the base material layer, but among these, in the laminate for a display device, it is preferable that the functional layer be disposed on the outermost surface.

As a method of forming the functional layer, for example, a method of applying the resin composition for a functional layer on a base material layer and curing it is included.

3. Base layer

The base layer in the present disclosure is a member that supports the functional layer and has transparency.

The base material layer is not particularly limited as long as it has transparency, and examples include a resin base material, a glass base material, etc.

(1) Resin base material

The resin constituting the resin substrate is not particularly limited as long as it can obtain a transparent resin substrate, and examples include polyimide resin, polyamide resin, and polyester resin. Examples of polyimide-based resins include polyimide, polyamidoimide, polyetherimide, and polyesterimide. Examples of polyester resins include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Among them, polyimide-based resins, polyamide-based resins, or mixtures thereof are preferable, and polyimide-based resins are more preferable because they have bending resistance and excellent hardness and transparency.

The polyimide-based resin is not particularly limited as long as it can obtain a transparent resin substrate, but among the above-mentioned resins, polyimide and polyamidoimide are preferably used.

(a) polyimide

Polyimide is obtained by reacting a tetracarboxylic acid component and a diamine component. The polyimide is not particularly limited as long as it has transparency and rigidity, but for example, it is selected from the group consisting of the structures represented by the following general formula (1) and the following general formula (3) in that it has excellent transparency and excellent rigidity. It is desirable to have at least one selected structure.

In the general formula (1), R ¹ is a tetravalent group that is a tetracarboxylic acid residue, R ² is a trans-cyclohexanediamine residue, trans-1,4-bismethylenecyclohexanediamine residue, 4,4' -Represents at least one type of divalent group selected from the group consisting of a diaminodiphenylsulfone residue, a 3,4'-diaminodiphenylsulfone residue, and a divalent group represented by the following general formula (2). n represents the number of repeating units and is 1 or more.

In the general formula (2), R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group, or a perfluoroalkyl group.

In the general formula (3), R ⁵ is a cyclohexanetetracarboxylic acid residue, a cyclopentanetetracarboxylic acid residue, a dicyclohexane-3,4,3',4'-tetracarboxylic acid residue, and 4 At least one tetravalent group selected from the group consisting of ,4'-(hexafluoroisopropylidene)diphthalic acid residues, R ⁶ , represents a divalent group that is a diamine residue.

n' represents the number of repeating units and is 1 or more.

In addition, “tetracarboxylic acid residue” refers to a residue obtained by removing four carboxyl groups from tetracarboxylic acid, and represents the same structure as the residue obtained by removing the acid dianhydride structure from tetracarboxylic dianhydride. In addition, “diamine residue” refers to a residue obtained by removing two amino groups from diamine.

In the general formula (1), R ¹ is a tetracarboxylic acid residue, and can be a residue obtained by removing the acid dianhydride structure from tetracarboxylic dianhydride. Examples of tetracarboxylic dianhydride include those described in International Publication No. 2018/070523. Examples of R ¹ in the general formula (1) include, among others, 4,4'-(hexafluoroisopropylidene)diphthalic acid residue, 3,3', since transparency is improved and rigidity is improved; 4,4'-Biphenyltetracarboxylic acid residue, pyromellitic acid residue, 2,3',3,4'-biphenyltetracarboxylic acid residue, 3,3',4,4'-benzophenone tetracarboxylic acid residue a boxylic acid moiety, a 3,3',4,4'-diphenylsulfonetetracarboxylic acid moiety, a 4,4'-oxydiphthalic acid moiety, a cyclohexanetetracarboxylic acid moiety, and a cyclopentanetetracarboxylic acid moiety. It is preferable to include at least one selected from the group consisting of 4,4'-(hexafluoroisopropylidene)diphthalic acid residue, 4,4'-oxydiphthalic acid residue, and 3,3',4, It is more preferable that it contains at least one type selected from the group consisting of 4'-diphenylsulfonetetracarboxylic acid residues.

In R ¹ , the total amount of these suitable residues is preferably 50 mol% or more, more preferably 70 mol% or more, and still more preferably 90 mol% or more.

Additionally, as R ¹ , a group consisting of a 3,3',4,4'-biphenyltetracarboxylic acid residue, a 3,3',4,4'-benzophenone tetracarboxylic acid residue, and a pyromellitic acid residue. A tetracarboxylic acid residue group (Group A) suitable for improving rigidity, such as at least one selected from 4'-biphenyltetracarboxylic acid residue, 3,3',4,4'-diphenylsulfonetetracarboxylic acid residue, 4,4'-oxydiphthalic acid residue, cyclohexanetetracarboxylic acid residue, and cyclo It is also preferable to use a mixture of at least one tetracarboxylic acid residue group (group B) suitable for improving transparency, such as at least one selected from the group consisting of pentanetetracarboxylic acid residues.

In this case, the content ratio of the tetracarboxylic acid residue group (group A) suitable for improving the rigidity and the tetracarboxylic acid residue group (group B) suitable for improving transparency is suitable for improving transparency. It is preferable that the tetracarboxylic acid residue group (Group A) suitable for improving rigidity is 0.05 mol or more and 9 mol or less, and more preferably 0.1 mol or more and 5 mol or less, relative to 1 mole of the tetracarboxylic acid residue group (Group B). It is preferable, and it is more preferable that it is 0.3 mol or more and 4 mol or less.

Examples of R ² in the general formula (1) include, among others, 4,4'-diaminodiphenylsulfone residue and 3,4'-diaminodiphenylsulfone, since transparency is improved and rigidity is improved. It is preferable that it is at least one type of divalent group selected from the group consisting of a residue and a divalent group represented by the general formula (2), 4,4'-diaminodiphenylsulfone residue, 3,4'-diamino It is more preferable that it is at least one type of divalent group selected from the group consisting of a diphenylsulfone residue and a divalent group represented by the general formula (2) above, wherein R ³ and R ⁴ are perfluoroalkyl groups.

Examples of R ⁵ in the general formula (3) include, among others, 4,4'-(hexafluoroisopropylidene)diphthalic acid residue, 3,3', since transparency is improved and rigidity is improved; It is preferred that it contains a 4,4'-diphenylsulfonetetracarboxylic acid residue and an oxydiphthalic acid residue.

For R ⁵ , it is preferable to contain 50 mol% or more of these suitable residues, more preferably 70 mol% or more, and even more preferably 90 mol% or more.

R ⁶ in the general formula (3) is a diamine residue, and can be a residue obtained by removing two amino groups from diamine. Examples of diamine include those described in International Publication No. 2018/070523. Examples of R ⁶ in the general formula (3) include, among others, 2,2'-bis(trifluoromethyl)benzidine residue, bis[4-(4-) because transparency is improved and rigidity is improved. Aminophenoxy)phenyl]sulfone residue, 4,4'-diaminodiphenylsulfone residue, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane residue, bis[4-(3 -aminophenoxy)phenyl]sulfone residue, 4,4'-diamino-2,2'-bis(trifluoromethyl)diphenyl ether residue, 1,4-bis[4-amino-2-(trifluoro) Romethyl)phenoxy]benzene residue, 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane residue, 4,4'-diamino-2-( Trifluoromethyl)diphenylether residue, 4,4'-diaminobenzanilide residue, N,N'-bis(4-aminophenyl)terephthalamide residue, and 9,9-bis(4-aminophenyl)flu. It preferably contains at least one type of divalent group selected from the group consisting of orene residues, 2,2'-bis(trifluoromethyl)benzidine residue, bis[4-(4-aminophenoxy)phenyl]sulfone, It is more preferable that it contains at least one type of divalent group selected from the group consisting of a residue and a 4,4'-diaminodiphenylsulfone residue.

In R ⁶ , it is preferable that the total amount of these suitable residues is 50 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol% or more.

Additionally, as R ⁶ , a bis[4-(4-aminophenoxy)phenyl]sulfone residue, a 4,4'-diaminobenzanilide residue, a N,N'-bis(4-aminophenyl)terephthalamide residue, para A group of diamine residues suitable for improving rigidity (group C), such as at least one selected from the group consisting of phenylenediamine residues, metaphenylenediamine residues, and 4,4'-diaminodiphenylmethane residues, 2 ,2'-bis(trifluoromethyl)benzidine residue, 4,4'-diaminodiphenylsulfone residue, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane residue, bis [4-(3-aminophenoxy)phenyl]sulfone residue, 4,4'-diamino-2,2'-bis(trifluoromethyl)diphenyl ether residue, 1,4-bis[4-amino- 2-(trifluoromethyl)phenoxy]benzene residue, 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane residue, 4,4'-dia A diamine residue group suitable for improving transparency, such as at least one selected from the group consisting of mino-2-(trifluoromethyl)diphenyl ether residue and 9,9-bis(4-aminophenyl)fluorene residue. It is also preferable to use a mixture of (Group D).

In this case, the content ratio of the diamine residue group (group C) suitable for improving the rigidity and the diamine residue group (group D) suitable for improving transparency is the diamine residue group (group D) suitable for improving transparency. ) Per mole, the diamine residue group (group C) suitable for improving rigidity is preferably 0.05 mol or more and 9 mol or less, more preferably 0.1 mol or more and 5 mol or less, and more preferably 0.3 mol or more and 4 mol or less. do.

In the structures represented by the general formula (1) and the general formula (3), n and n' each independently represent the number of repeating units and are 1 or more. The number n of repeating units in polyimide may be appropriately selected depending on the structure and is not particularly limited. The average number of repeating units can be, for example, 10 to 2000, and is preferably 15 to 1000.

In addition, the polyimide may contain a polyamide structure in part. Examples of the polyamide structure that may be included include a polyamideimide structure containing a tricarboxylic acid residue such as trimellitic anhydride, and a polyamide structure containing a dicarboxylic acid residue such as terephthalic acid. .

In order to improve transparency and surface hardness, at least one of the tetravalent group that is the tetracarboxylic acid residue of R ¹ or R ⁵ and the divalent group that is the diamine residue of R ² or R ⁶ is an aromatic ring. It contains at least one selected from the group consisting of a structure in which (i) a fluorine atom, (ii) an aliphatic ring, and (iii) an aromatic ring are connected to each other by a sulfonyl group or an alkylene group that may be substituted with fluorine. It is desirable. When the polyimide contains at least one type selected from the group consisting of a tetracarboxylic acid residue having an aromatic ring and a diamine residue having an aromatic ring, the molecular skeleton becomes rigid and the orientation increases, and surface hardness is improved, but the rigid aromatic ring The skeleton tends to have an absorption wavelength extending to a long wavelength, so the transmittance in the visible light region tends to decrease. On the other hand, when the polyimide contains (i) a fluorine atom, transparency is improved in that charge transfer of the electronic state in the polyimide skeleton can be made difficult.

Additionally, when the polyimide contains (ii) an aliphatic ring, transparency is improved in that the movement of charge within the polyimide skeleton can be inhibited by breaking the conjugation of π electrons within the polyimide skeleton. In addition, if the polyimide (iii) contains a structure in which aromatic rings are linked to a sulfonyl group or an alkylene group that may be substituted with fluorine, the movement of charge within the skeleton may be inhibited by breaking the conjugation of π electrons in the polyimide skeleton. Transparency is improved in that it can be done.

Among them, in terms of improving transparency and surface hardness, at least one of the tetravalent group that is the tetracarboxylic acid residue of R ¹ or R ⁵ and the divalent group that is the diamine residue of R ² or R ⁶ is , it is preferable that it contains an aromatic ring and a fluorine atom, and the divalent group which is the diamine residue of ^R2 or ^R6 preferably contains an aromatic ring and a fluorine atom.

Specific examples of such polyimides include those having a specific structure described in International Publication No. 2018/070523.

Polyimide can be synthesized by a known method. Additionally, commercially available polyimide may be used. Commercially available products of polyimide include, for example, Neoprem (registered trademark) manufactured by Mitsubishi Gas Chemical Co., Ltd.

The weight average molecular weight of polyimide is preferably, for example, 3,000 to 500,000, more preferably 5,000 to 300,000, and even more preferably 10,000 to 200,000. If the weight average molecular weight is too small, sufficient strength may not be obtained, and if the weight average molecular weight is too large, the viscosity increases and solubility decreases, so a base material layer with a smooth surface and uniform thickness cannot be obtained. There is.

In addition, the weight average molecular weight of polyimide can be measured by gel permeation chromatography (GPC). Specifically, the polyimide was set as an N-methylpyrrolidone (NMP) solution with a concentration of 0.1% by mass, a 30mmol% LiBr-NMP solution with a water content of 500ppm or less was used as the developing solvent, and the coating agent GPC device (HLC- 8120, column used: GPC LF-804 manufactured by SHODEX), and the measurement was performed under the conditions of 50 μL sample volume, 0.4 mL/min solvent flow rate, and 37°C. The weight average molecular weight is determined based on a polystyrene standard sample of the same concentration as the sample.

(b) polyamideimide

The polyamideimide is not particularly limited as long as it can obtain a transparent resin substrate, and includes, for example, a first block containing a dianhydride-derived structural unit and a diamine-derived structural unit, and an aromatic dicarbonyl compound. and those having a second block containing structural units derived from aromatic diamine and structural units derived from aromatic diamine. In the polyamideimide, the dianhydride is, for example, biphenyltetracarboxylic dianhydride (BPDA) and 2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA). It can be included. Additionally, the diamine may include bistrifluoromethylbenzidine (TFDB). That is, the polyamideimide is a polyamideimide precursor having a first block in which monomers containing dianhydride and diamine are copolymerized, and a second block in which monomers containing an aromatic dicarbonyl compound and an aromatic diamine are copolymerized. It has an imidized structure.

The polyamideimide has excellent optical properties as well as thermal and mechanical properties by having a first block containing an imide bond and a second block containing an amide bond. In particular, thermal stability and optical properties can be improved by using bistrifluoromethylbenzidine (TFDB) as the diamine forming the first block. Additionally, by using 2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and biphenyltetracarboxylic dianhydride (BPDA) as dianhydride forming the first block, It is possible to improve birefringence and secure heat resistance.

The dianhydride forming the first block includes two types of dianhydride, namely 6FDA and BPDA. In the first block, a polymer to which TFDB and 6FDA are bonded and a polymer to which TFDB and BPDA are bonded may be contained separately based on separate repeating units, may be arranged regularly within the same repeating unit, or may be completely arranged. It may be included in a random arrangement.

Among the monomers forming the first block, it is preferable that BPDA and 6FDA are included as dianhydride in a molar ratio of 1:3 to 3:1. This is because it not only secures optical properties, but also suppresses deterioration of mechanical properties and heat resistance, and has excellent birefringence.

The molar ratio of the first block and the second block is preferably 5:1 to 1:1. When the content of the second block is significantly low, the effects of improving thermal stability and mechanical properties by the second block may not be sufficiently obtained. In addition, when the content of the second block is higher than the content of the first block, thermal stability and mechanical properties may be improved, but optical properties such as yellowness and transmittance may decrease, and birefringence characteristics may also increase. there is. In addition, the first block and the second block may be a random copolymer or a block copolymer. The repetition unit of the block is not particularly limited.

As the aromatic dicarbonyl compound forming the second block, for example, terephthaloyl chloride (TPC), terephthalic acid, isophthaloyl dichloride (Iso-phthaloyl dichloride), and 4,4 One or more species selected from the group consisting of '-benzoyl dichloride (4,4'-benzoyl chloride) can be mentioned. Preferably, it may be one or more selected from terephthaloyl chloride (TPC) and isophthaloyl dichloride (Iso-phthaloyl dichloride).

As the diamine forming the second block, for example, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane (HFBAPP), bis(4-(4-aminophenoxy)phenyl) Sulfone (BAPS), bis(4-(3-aminophenoxy)phenyl)sulfone (BAPSM), 4,4'-diaminodiphenylsulfone (4DDS), 3,3'-diaminodiphenylsulfone (3DDS) , 2,2-bis (4- (4-aminophenoxy) phenylpropane (BAPP), 4,4'-diaminodiphenylpropane (6HDA), 1,3-bis (4-aminophenoxy) benzene ( 134APB), 1,3-bis(3-aminophenoxy)benzene (133APB), 1,4-bis(4-aminophenoxy)biphenyl (BAPB), 4,4'-bis(4-amino-2) -Trifluoromethylphenoxy)biphenyl (6FAPBP), 3,3-diamino-4,4-dihydroxydiphenylsulfone (DABS), 2,2-bis (3-amino-4-hydroxyoxy) Phenyl)propane (BAP), 4,4'-diaminodiphenylmethane (DDM), 4,4'-oxydianiline (4-ODA), and 3,3'-oxydianiline (3-ODA). and diamines having one or more types of flexible groups selected from the group.

When using an aromatic dicarbonyl compound, it is easy to realize high thermal stability and mechanical properties, but it may exhibit high birefringence due to the benzene ring in the molecular structure. Therefore, in order to suppress the decrease in birefringence due to the second block, it is preferable to use a diamine in which a flexible group is introduced into the molecular structure. Specifically, diamines include bis(4-(3-aminophenoxy)phenyl)sulfone (BAPSM), 4,4'-diaminodiphenylsulfone (4DDS), and 2,2-bis(4-(4- More preferably, it is one or more diamines selected from aminophenoxy)phenyl)hexafluoropropane (HFBAPP). In particular, diamines such as BAPSM, where the length of the flexible group is long and the position of the substituent in the meta position, can exhibit excellent birefringence.

Dianhydrides including biphenyltetracarboxylic dianhydride (BPDA) and 2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), and bistrifluoromethylbenzidine (TFDB) The polyamidoimide precursor, which includes in its molecular structure a first block in which a diamine containing a copolymerization and a second block in which an aromatic dicarbonyl compound and an aromatic diamine are copolymerized, has a weight average molecular weight measured by GPC, for example For example, it is preferable that it is 200,000 or more and 215,000 or less, and it is preferable that the viscosity is, for example, 2400 poise or more and 2600 poise or less.

Polyamideimide can be obtained by imidizing a polyamideimide precursor. Additionally, a polyamideimide film can be obtained using polyamideimide. For a method of imidizing a polyamideimide precursor and a method of producing a polyamideimide film, refer to, for example, Japanese Patent Publication No. 2018-506611.

(2) Glass substrate

The glass constituting the glass substrate is not particularly limited as long as it has transparency, and examples include silicate glass and silica glass. Among them, borosilicate glass, aluminosilicate glass, and aluminoborosilicate glass are preferable, and alkali-free glass is more preferable. Examples of commercially available glass substrates include ultra-thin glass G-Leaf from Nippon Denki Glass Co., Ltd. and ultra-thin glass from Matsunami Glass Co., Ltd.

Additionally, it is preferable that the glass constituting the glass substrate is chemically strengthened glass. Chemically strengthened glass is desirable because it has excellent mechanical strength and can be made as thin as possible. Chemically strengthened glass is typically glass whose mechanical properties have been strengthened through a chemical method by partially exchanging ionic species, such as changing sodium to potassium, near the surface of the glass, and has a compressive stress layer on the surface.

Examples of glass constituting the chemically strengthened glass base material include aluminosilicate glass, soda lime glass, borosilicate glass, lead glass, alkali barium glass, and aluminoborosilicate glass.

Examples of commercially available products based on chemically strengthened glass include Corning's Gorilla Glass, AGC's Dragontrail, and Shot's chemically strengthened glass.

(3) Composition of base layer

As the base material layer, among those mentioned above, a polyimide-based resin base material or a glass base material containing polyimide-based resin is preferable. This is because it can be used as a base layer that has bending resistance and excellent hardness and transparency.

The thickness of the base layer is not particularly limited as long as it has flexibility and is appropriately selected depending on the type of base layer, etc.

The thickness of the resin substrate is preferably, for example, 10 μm or more and 100 μm or less, and more preferably 25 μm or more and 80 μm or less. When the thickness of the resin base material is within the above range, good flexibility can be obtained and sufficient hardness can be obtained. Additionally, curling of the display device laminate can be suppressed. Additionally, it is desirable in terms of reducing the weight of the laminate for a display device.

The thickness of the glass substrate is, for example, preferably 200 μm or less, more preferably 15 μm or more and 100 μm or less, more preferably 20 μm or more and 90 μm or less, and especially preferably 25 μm or more and 80 μm or less. do. When the thickness of the glass base material is within the above range, good flexibility can be obtained and sufficient hardness can be obtained. Additionally, curling of the display device laminate can be suppressed. Additionally, it is desirable in terms of reducing the weight of the laminate for a display device.

4. Second functional layer

The laminate for a display device in the present disclosure may have a second functional layer between the base layer and the functional layer, or on the side of the functional layer opposite to the base layer. Examples of the second functional layer include a hard coat layer, an anti-reflection layer, an anti-glare layer, an anti-scattering layer, and a primer layer.

Additionally, the second functional layer may be a single layer or may be a multilayer. In addition, the second functional layer may be a layer having a single function, or may have a plurality of layers having different functions.

(1) Hard coat layer

The laminate for a display device in the present disclosure may have a hard coat layer 4 between the base material layer 2 and the functional layer 3, for example, as shown in FIG. 4 . The hard coat layer is a member for increasing surface hardness. By disposing the hard coat layer, scratch resistance can be improved. In particular, when the base material layer is a resin base material, scratch resistance can be effectively improved by providing a hard coat layer.

As a material for the hard coat layer, for example, organic materials, inorganic materials, organic-inorganic composite materials, etc. can be used.

Among these, it is preferable that the material of the hard coat layer is an organic material. Specifically, it is preferable that the hard coat layer contains a cured product of a resin composition containing a polymerizable compound. A cured product of a resin composition containing a polymerizable compound can be obtained by subjecting the polymerizable compound to a polymerization reaction by a known method, using a polymerization initiator as necessary.

In addition, the polymerizable compound can be used in the same manner as described in the above functional layer section, so description here is omitted.

The hard coat layer may contain a polymerization initiator as needed. In addition, the polymerization initiator can be used in the same manner as described in the above functional layer section, so description here is omitted.

Additionally, the hard coat layer may contain an antistatic agent. Among these, when the functional layer does not contain an antistatic agent, it is preferable that the hard coat layer contains an antistatic agent. Antistatic properties can be imparted to a laminate for a display device. Additionally, by adjusting the content of the antistatic agent, the absolute value of the electric charge on the surface on the functional layer side of the display device laminate after the eraser test can be adjusted so that it falls within a predetermined range.

The type and content of the antistatic agent can be the same as the type and content of the antistatic agent in the functional layer.

The hard coat layer may further contain additives as needed. The additive is appropriately selected depending on the function provided to the hard coat layer, and is not particularly limited, but examples include inorganic particles, organic particles, ultraviolet absorbers, infrared absorbers, antifouling agents, antiglare agents, leveling agents, surfactants, lubricants, etc. agents, various sensitizers, flame retardants, adhesion imparting agents, polymerization inhibitors, antioxidants, light stabilizers, surface modifiers, etc.

The thickness of the hard coat layer may be appropriately selected depending on the function of the hard coat layer and the intended use of the display device laminate. The thickness of the hard coat layer is preferably, for example, 0.5 μm or more and 50 μm or less, more preferably 1.0 μm or more and 40 μm or less, further preferably 1.5 μm or more and 30 μm or less, and especially 2 μm or more and 20 μm or less. desirable. If the thickness of the hard coat layer is within the above range, sufficient hardness can be obtained as a hard coat layer.

As a method of forming the hard coat layer, for example, a method of applying a resin composition for a hard coat layer containing the polymerizable compound or the like onto the base material layer and curing the resin composition is included.

(2) Anti-reflection layer

The laminate for a display device in the present disclosure may have an anti-reflection layer as a second functional layer. The antireflection layer is usually provided on the surface of the functional layer opposite to the base layer.

The antireflection layer may be composed of a single layer or may be composed of multiple layers.

As the antireflection layer, a general antireflection layer can be applied, for example, a single layer film containing a material with a lower refractive index than the hard coat layer, a multilayer film having a high refractive index layer and a low refractive index layer from the hard coat layer side, or a hard coat layer. Examples include a multilayer film in which high refractive index layers and low refractive index layers are alternately laminated from the side, and a multilayer film in which a medium refractive index layer, a high refractive index layer, and a low refractive index layer are sequentially stacked from the hard coat layer side.

When the anti-reflection layer is a single-layer film, the material contained in the single-layer film may be any material that has a lower refractive index than the hard coat layer, and examples include magnesium fluoride.

In addition, when the antireflection layer is a multilayer film, the refractive index of the low refractive index layer is preferably, for example, 1.45 or less, and more preferably 1.40 or less. By setting the refractive index of the low refractive index layer within the above range, anti-reflection properties become good. Additionally, the practical lower limit of the refractive index of the low refractive index layer is 1.10 or more.

Examples of the low refractive index layer include those containing hydrolyzed polycondensates of metal alkoxides, those containing low refractive index resins, those containing low refractive index particles, those containing binder resin and low refractive index particles, etc. I can hear it.

A hydrolyzed polycondensate of a metal alkoxide can be obtained, for example, by the sol-gel method.

Examples of low-refractive-index resins include fluororesins.

In addition, the thickness of the low refractive index layer is preferably about 1/4 of the wavelength range of visible light (around 100 nm), so for example, it is preferably 60 nm or more and 200 nm or less, more preferably 75 nm or more and 180 nm or less, and 90 nm or more. It is more preferable that it is 150 nm.

Methods for forming the low refractive index layer include wet methods and dry methods. Wet methods include a method of forming by a sol-gel method using a metal alkoxide, etc., a method of forming by applying a low refractive index resin, and a method of forming by applying a composition for a low refractive index layer containing a binder resin and low refractive index particles. You can. As a dry method, a method of forming by a physical vapor growth method or a chemical vapor growth method using low refractive index particles is included. The wet method is excellent in terms of production efficiency, and among them, the method of forming by applying a composition for a low refractive index layer containing a binder resin and low refractive index particles is preferable.

In addition, the refractive index of the high refractive index layer is preferably, for example, 1.55 or more and 1.85 or less, and more preferably 1.58 or more and 1.70 or less. By setting the refractive index of the high refractive index layer to a predetermined value or more, anti-reflection properties become good. Additionally, the practical upper limit of the high refractive index layer is 1.85 or less.

Examples of the high refractive index layer include those containing binder resin and high refractive index particles.

Examples of high refractive index particles include antimony pentoxide, zinc oxide, titanium oxide, cerium oxide, tin-doped indium oxide, antimony-doped tin oxide, yttrium oxide, and zirconium oxide.

The average particle diameter of the high refractive index particles is preferably, for example, 5 nm or more and 200 nm or less, more preferably 5 nm or more and 100 nm or less, and even more preferably 10 nm or more and 80 nm or less. By setting the average particle diameter to 5 nm or more, it is possible to easily suppress agglomeration of particles, and by setting the average particle diameter to 200 nm or less, it is possible to easily suppress a decrease in visibility due to whitening due to particle diffusion.

From the viewpoint of increasing the refractive index of the coating film and balancing the strength of the coating film, the content of the high refractive index particles is preferably 50 parts by mass or more and 500 parts by mass or less, and 100 parts by mass or more and 450 parts by mass or less, with respect to 100 parts by mass of the binder resin. It is more preferable that it is 200 parts by mass or more and 430 parts by mass or less.

Examples of the binder resin contained in the high refractive index layer include cured products of curable resin compositions. As the curable resin composition, those similar to those exemplified for the hard coat layer can be used, and a photocurable resin composition is suitable.

Additionally, the thickness of the high refractive index layer is preferably, for example, 200 nm or less, more preferably 50 nm or more and 180 nm or less, and even more preferably 90 nm or more and 160 nm or less. By setting the thickness of the high refractive index layer within the above range, low reflectivity can be exhibited in a wide wavelength range in the visible light region (380 nm to 780 nm).

As a method of forming the high refractive index layer, for example, a method of forming the high refractive index layer by applying a composition for a high refractive index layer containing a binder resin and high refractive index particles is included.

The thickness of the anti-reflection layer can be the same as the thickness of a general anti-reflection layer, and is appropriately selected depending on the layer structure of the anti-reflection layer.

Examples of the method for forming the anti-reflection layer include a coating method and a vapor deposition method, and are appropriately selected depending on the material of the anti-reflection layer.

5. Shock absorbing layer

The laminate for a display device in the present disclosure may have an impact absorption layer on the surface of the base layer opposite to the functional layer or between the base layer and the functional layer. By disposing the shock absorption layer, shock can be absorbed when shock is applied to the display device laminate, and shock resistance can be improved. Additionally, when the base layer is a glass base, cracking of the glass base can be suppressed.

The material of the shock absorbing layer is not particularly limited as long as it has shock absorbing properties and can obtain a transparent shock absorbing layer, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), urethane resin, epoxy resin, Polyimide, polyamidoimide, acrylic resin, triacetylcellulose (TAC), silicone resin, etc. can be mentioned. These materials may be used individually or in combination of two or more types.

The shock absorbing layer may further contain additives, if necessary. Examples of additives include inorganic particles, organic particles, ultraviolet absorbers, antioxidants, light stabilizers, surfactants, and adhesion improvers.

The thickness of the shock absorbing layer may be any thickness that can absorb the shock. For example, it is preferably 7 μm or more and 150 μm or less, more preferably 10 μm or more and 120 μm or less, and even more preferably 15 μm or more and 100 μm or less. You can do this.

As the shock absorption layer, for example, a resin film may be used. Additionally, a shock absorption layer may be formed, for example, by applying a shock absorption layer composition on the base material layer.

6. Adhesive layer for patching

The laminate for a display device in the present disclosure may have an adhesive layer 6 for sticking on the surface of the base material layer 2 opposite to the functional layer 3, as shown in FIG. 5, for example. . Through the adhesive layer for sticking, the laminate for a display device can be bonded to, for example, a display panel.

The adhesive used in the adhesive layer for sticking is not particularly limited as long as it has transparency and can adhere the display device laminate to the display panel, etc., for example, thermosetting adhesive, ultraviolet curing adhesive, two-component curing adhesive, Heat-melt adhesives, pressure-sensitive adhesives (so-called adhesives), etc. can be mentioned.

Among them, for example, as shown in FIG. 6, this is the case where the shock absorbing layer 5 is disposed on the surface of the base material layer 2 opposite to the functional layer 3, and the base material of the shock absorbing layer 5 In the case where the adhesive layer 6 for sticking is disposed on the surface opposite to the layer 2 and the interlayer adhesive layer 7 described later is disposed between the base material layer 2 and the shock absorbing layer 5, The adhesive layer and the interlayer adhesive layer preferably contain a pressure-sensitive adhesive, that is, they are preferably a pressure-sensitive adhesive layer. In general, the pressure-sensitive adhesive layer is a relatively flexible layer among adhesive layers containing the above adhesives. By disposing the shock absorbing layer between relatively flexible pressure-sensitive adhesive layers, impact resistance can be improved. This is because the pressure-sensitive adhesive layer is relatively flexible and easily deformed, so when an impact is applied to the display device laminate, the deformation of the shock-absorbing layer is not suppressed by the pressure-sensitive adhesive layer, and the shock-absorbing layer becomes easily deformed, resulting in greater deformation. It is thought that it has a shock absorption effect.

Pressure-sensitive adhesives used in the pressure-sensitive adhesive layer include, for example, acrylic adhesives, silicone-based adhesives, rubber-based adhesives, urethane-based adhesives, etc., and can be appropriately selected depending on the material of the shock absorbing layer, etc. Among them, acrylic adhesives are preferable. This is because it has excellent transparency, weather resistance, durability, and heat resistance, and is low cost.

The thickness of the adhesive layer for sticking is preferably, for example, 10 μm or more and 100 μm or less, more preferably 25 μm or more and 80 μm or less, and further preferably 40 μm or more and 60 μm or less. If the thickness of the adhesive layer for sticking is too thin, there is a risk that the display device laminate and the display panel may not be sufficiently bonded. In addition, when the adhesive layer for sticking is a pressure-sensitive adhesive layer, if the thickness of the adhesive layer for sticking is too thin, the effect of making it easy to deform the shock absorbing layer when an impact is applied to the display device laminate may not be sufficiently obtained. . On the other hand, if the thickness of the adhesive layer for sticking is too thick, flexibility may be impaired.

As the adhesive layer for sticking, for example, you may use an adhesive film. Additionally, for example, the adhesive composition may be applied on a support or a base layer to form an adhesive layer for sticking.

7. Interlayer adhesive layer

In the laminate for a display device in the present disclosure, an interlayer adhesive layer may be disposed between each layer.

The adhesive used in the interlayer adhesive layer can be similar to the adhesive used in the adhesive layer for sticking.

Among them, as described above, this is the case where the shock absorbing layer is disposed on the side of the base material layer opposite to the functional layer, the adhesive layer for sticking is disposed on the side of the shock absorbing layer opposite to the base layer, and the base material layer and when an interlayer adhesive layer is disposed between the shock absorbing layers, the adhesive layer for sticking and the interlayer adhesive layer preferably contain a pressure-sensitive adhesive, that is, they are preferably a pressure-sensitive adhesive layer.

The pressure-sensitive adhesive layer can be used in the same manner as the pressure-sensitive adhesive layer used in the adhesive layer for sticking.

The thickness, formation method, etc. of the interlayer adhesive layer can be similar to the thickness and formation method of the above-mentioned adhesive layer for sticking.

8. Other points of laminate for display device

The thickness of the display device laminate in the present disclosure is preferably, for example, 10 μm or more and 500 μm or more, more preferably 20 μm or more and 400 μm or more, and even more preferably 30 μm or more and 300 μm or more. If the thickness of the display device laminate is within the above range, flexibility can be improved.

The laminate for a display device in the present disclosure can be used as a front plate disposed on a viewer side of the display panel in a display device. Among them, the laminate for a display device in the present disclosure can be suitably used for a front panel in a flexible display device such as a foldable display, a rollable display, or a bendable display. In particular, the laminate for a display device in the present disclosure can be suitably used for a front panel in a foldable display because it can improve wear resistance at a bent portion.

In addition, the laminate for a display device in the present disclosure can be used in display devices such as smartphones, tablet terminals, wearable terminals, personal computers, televisions, digital signage, public information displays (PID), and vehicle-mounted displays, for example. It can be used on the front panel of

B. Display device

The display device in the present disclosure includes a display panel and the above-described display device laminate disposed on an observer side of the display panel.

7 is a schematic cross-sectional view showing an example of a display device in the present disclosure. As shown in FIG. 7 , the display device 20 includes a display panel 21 and a display device laminate 1 disposed on the viewer side of the display panel 21. In the display device 20, the display device laminate 1 and the display panel 21 can be bonded, for example, through the adhesive layer 6 for sticking of the display device laminate 1.

When the laminate for a display device in the present disclosure is disposed on the surface of the display device, the functional layer is disposed on the outer side and the base layer is disposed on the inner side.

The method of disposing the laminate for a display device in the present disclosure on the surface of the display device is not particularly limited, but includes, for example, a method using an adhesive layer.

Examples of the display panel in the present disclosure include display panels used in display devices such as organic EL displays and liquid crystal displays.

The display device in the present disclosure may have a touch panel member between the display panel and the display device laminate.

It is preferable that the display device in the present disclosure is, among others, a flexible display device such as a foldable display, a rollable display, or a bendable display.

Additionally, it is preferable that the display device in the present disclosure is foldable. That is, it is preferable that the display device in the present disclosure is a foldable display. The display device in the present disclosure has excellent wear resistance at bent portions and is suitable as a foldable display.

Additionally, the present disclosure is not limited to the above embodiments. The above-mentioned embodiment is an example, and anything that has substantially the same structure as the technical idea described in the claims of the present disclosure and exhibits similar functions and effects is included in the technical scope of the present disclosure.

Example

Hereinafter, examples and comparative examples will be shown and the present disclosure will be further explained.

[Example 1]

(1) Formation of hard coat layer A

First, each component was blended so as to have the composition shown below, and resin composition 1 for hard coat layer was obtained.

(Composition of resin composition 1 for hard coat layer)

· Urethane acrylate (product name “8UX-141A”, manufactured by Taisei Fine Chemicals): 100 parts by mass (converted to 100% solid content)

· Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 4 parts by mass

· Leveling agent (product name “BYK-UV3535”, manufactured by Big Chemie Japan): 0.5 parts by mass (converted to 100% solid content)

· Methyl isobutyl ketone: 250 parts by mass

Next, using a polyimide film with a thickness of 80 μm (product name “Neoprim”, manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a base layer, the above-mentioned resin composition 1 for hard coat layer was applied with a bar coater on the base layer. Thus, a coating film was formed. Then, the solvent in the coating film was evaporated by heating this coating film at 80°C for 1 minute, and using an ultraviolet irradiation device (Light Source H Bulb, manufactured by Fusion UV Systems Japan), ultraviolet rays were irradiated at an oxygen concentration of 100 ppm or less with an integrated light amount of The coating film was cured by irradiating to 70 mJ/cm ² , and a hard coat layer A with a thickness of 9.0 μm was formed as a second functional layer.

(2) Formation of hard coat layer B

First, each component was blended so as to have the composition shown below, and resin composition 2 for hard coat layer was obtained.

(Composition of resin composition 2 for hard coat layer)

· Urethane acrylate (product name “8UX-015A”, manufactured by Taisei Fine Chemicals): 100 parts by mass (converted to 100% solid content)

· Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 4 parts by mass

· Antifouling agent (product name “DAC-HP”, manufactured by Daikin): 0.5 parts by mass (value converted to 100% solid content)

· Antistatic agent (product name “Beam Set MT-2”, manufactured by Arakawa Chemical Industry Co., Ltd.): 1.5 parts by mass (converted to 100% solid content)

· Methyl isobutyl ketone: 250 parts by mass

Next, the resin composition for hard coat layer 2 was applied onto the hard coat layer A using a bar coater to form a coating film. Then, the solvent in the coating film was evaporated by heating this coating film at 50°C for 1 minute, and using an ultraviolet irradiation device (Light Source H Bulb, manufactured by Fusion UV Systems Japan), ultraviolet rays were irradiated at an oxygen concentration of 100 ppm or less with an integrated light amount. The coating film was cured by irradiating to 360 mJ/cm ² , and a hard coat layer B with a thickness of 3.0 μm was formed as a functional layer. In this way, a laminate having the base material layer, hard coat layer A (second functional layer), and hard coat layer B (functional layer) in this order was obtained.

[Comparative Example 1]

In forming the hard coat layer B (functional layer), a laminate was produced in the same manner as in Example 1, except that the following resin composition 3 for hard coat layer was used.

(Composition of resin composition 3 for hard coat layer)

· Urethane acrylate (product name “8UX-141A”, manufactured by Taisei Fine Chemicals): 100 parts by mass (converted to 100% solid content)

· Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 4 parts by mass

· Antifouling agent (product name “DAC-HP”, manufactured by Daikin): 0.5 parts by mass (value converted to 100% solid content)

· Methyl isobutyl ketone: 250 parts by mass

[Example 2]

A laminate was produced in the same manner as in Example 1, except that a PET film (“Cosmoshine A4160” manufactured by Toyobo Corporation) with a thickness of 50 μm was used as the base layer.

[Example 3]

In forming the hard coat layer B (functional layer), the resin composition 4 for the hard coat layer below was used, and a laminate was produced in the same manner as in Example 2, except that the thickness was set to 4.0 μm.

(Composition of resin composition 4 for hard coat layer)

· Urethane acrylate (product name “8UX-141A”, manufactured by Taisei Fine Chemicals): 100 parts by mass (converted to 100% solid content)

· Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 4 parts by mass

· Antifouling agent (product name “DAC-HP”, manufactured by Daikin): 0.5 parts by mass (value converted to 100% solid content)

· Antistatic agent (product name “Beam Set MT-2”, manufactured by Arakawa Chemical Industry Co., Ltd.): 2 parts by mass (converted to 100% solid content)

· Methyl isobutyl ketone: 250 parts by mass

[Example 4]

Except that the hard coat layer A (second functional layer) was not formed, and in the formation of the hard coat layer B (functional layer), the above-mentioned resin composition 4 for hard coat layer was used and the thickness was set to 3.5 μm. , a laminate was produced in the same manner as in Example 2.

[Example 5]

In forming the hard coat layer B (functional layer), a laminate was produced in the same manner as in Example 3, except that the thickness was set to 3.3 μm.

[Example 6]

In forming the hard coat layer B (functional layer), a laminate was produced in the same manner as in Example 3, except that the thickness was set to 3.8 μm.

[Example 7]

In forming the hard coat layer B (functional layer), the following resin composition 5 for hard coat layer was used, and a laminate was produced in the same manner as in Example 3, except that the thickness was 3.5 μm.

(Composition of resin composition 5 for hard coat layer)

· Urethane acrylate (product name “8UX-141A”, manufactured by Taisei Fine Chemicals): 50 parts by mass (converted to 100% solid content)

· Urethane acrylate (product name “8UX-015A”, manufactured by Taisei Fine Chemicals): 50 parts by mass (converted to 100% solid content)

· Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 4 parts by mass

· Antifouling agent (product name “DAC-HP”, manufactured by Daikin): 0.5 parts by mass (value converted to 100% solid content)

· Antistatic agent (product name “Beam Set MT-2”, manufactured by Arakawa Chemical Industry Co., Ltd.): 2 parts by mass (converted to 100% solid content)

· Methyl isobutyl ketone: 250 parts by mass

[Example 8]

A laminate was produced in the same manner as in Example 2, except that Resin Composition 6 for a hard coat layer containing an antistatic agent in the second functional layer was used.

(Composition of resin composition 6 for hard coat layer)

· Urethane acrylate (product name “8UX-141A”, manufactured by Taisei Fine Chemicals): 100 parts by mass (converted to 100% solid content)

· Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 4 parts by mass

· Leveling agent (product name “BYK-UV3535”, manufactured by Big Chemie Japan): 0.5 parts by mass (converted to 100% solid content)

· Antistatic agent (product name “Beam Set MT-2”, manufactured by Arakawa Chemical Industry Co., Ltd.): 2.5 parts by mass (converted to 100% solid content)

· Methyl isobutyl ketone: 250 parts by mass

[Example 9]

A laminate was produced in the same manner as in Example 8, except that Resin Composition 7 for a hard coat layer without an antistatic agent was used in the functional layer.

(Composition of resin composition 7 for hard coat layer)

· Urethane acrylate (product name “8UX-015A”, manufactured by Taisei Fine Chemicals): 100 parts by mass (converted to 100% solid content)

· Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 4 parts by mass

· Antifouling agent (product name “DAC-HP”, manufactured by Daikin): 0.5 parts by mass (value converted to 100% solid content)

· Methyl isobutyl ketone: 250 parts by mass

[Example 10]

A laminate was produced in the same manner as in Example 9, except that the thickness of the functional layer was 5.8 μm.

[Example 11]

A laminate was produced in the same manner as in Example 9, except that the thickness of the functional layer was 9.4 μm.

[Example 12]

First, resin composition 8 for hard coat layer was applied on the hard coat layer A (second functional layer) of Example 2 with a bar coater to form a coating film. Then, the solvent in the coating film was evaporated by heating this coating film at 80°C for 1 minute, and using an ultraviolet irradiation device (Light Source H Bulb, manufactured by Fusion UV Systems Japan), ultraviolet rays were irradiated at an oxygen concentration of 100 ppm or less with an integrated light amount of The coating film was cured by irradiating to 70 mJ/cm ² , and a hard coat layer B (functional layer) with a thickness of 3.0 μm was formed as a functional layer.

(Composition of resin composition 8 for hard coat layer)

· Urethane acrylate (product name “8UX-015A”, manufactured by Taisei Fine Chemicals): 100 parts by mass (converted to 100% solid content)

· Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 4 parts by mass

· Leveling agent (product name “BYK-UV3535”, manufactured by Big Chemie Japan): 0.5 parts by mass (converted to 100% solid content)

· Antistatic agent (product name “Beam Set MT-2”, manufactured by Arakawa Chemical Industry Co., Ltd.): 1.5 parts by mass (converted to 100% solid content)

· Methyl isobutyl ketone: 250 parts by mass

Next, on the hard coat layer B (functional layer), an anti-reflection layer (low refractive index) with a thickness of 100 nm was produced using the composition for an anti-reflection layer (low refractive index) of the following composition under the following processing conditions, and laminated. got a sieve

(Composition of composition for anti-reflection layer (low refractive index))

· Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass

· Urethane acrylate (product name “8UX-047A”, manufactured by Taisei Fine Chemicals): 25 parts by mass

· Multifunctional acrylate (product name “M-510”, manufactured by Toa Kosei Corporation): 45 parts by mass

· Pentaerythritol tri and tetraacrylate (product name “M-450”, manufactured by Toagosei Corporation): 30 parts by mass

· Low refractive index particles (hollow silica, average primary particle diameter 50 nm, manufactured by Nikki Shokubai Chemicals): 120 parts by mass (value converted to 100% solid content)

· Low refractive index particles (silica, average primary particle diameter 12 nm, manufactured by Nissan Chemical Industries, Ltd.): 15 parts by mass (value converted to 100% solid content)

· Methyl isobutyl ketone: 270 parts by mass

· Isopropyl alcohol: 40 parts by mass

(processing conditions)

After heating at 90°C for 1 minute, ultraviolet rays were irradiated to an integrated light amount of 500mJ/cm ² at an oxygen concentration of 100ppm or less.

[Example 13]

On the hard coat layer B (functional layer) described in Example 12, an anti-reflection layer (high refractive index) with a thickness of 80 nm was produced using the composition for an anti-reflection layer (high refractive index) of the following composition under the following processing conditions. Next, an antireflection layer (low refractive index) similar to that produced in Example 12 was produced, and a laminate was obtained.

(Composition of composition for anti-reflection layer (high refractive index))

· Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass

· Pentaerythritol (tri/tetra) acrylate (product name “PETIA”, manufactured by Daicel Allnex): 80 parts by mass

· Multifunctional acrylate (product name “M-510”, manufactured by Toa Kosei Corporation): 20 parts by mass

· High refractive index particles (zirconia, average primary particle diameter 20 nm, manufactured by CIK Nanotech): 120 parts by mass (converted to 100% solid content)

· Methyl isobutyl ketone: 270 parts by mass

· Isopropyl alcohol: 40 parts by mass

(processing conditions)

After heating at 70°C for 1 minute, ultraviolet rays were irradiated to an integrated light amount of 60mJ/cm ² at an oxygen concentration of 100ppm or less.

[Example 14]

A laminate was obtained in the same manner as in Example 13, except that the thickness of the antireflection layer (high refractive index) was 190 nm.

[Comparative Example 2]

In forming the hard coat layer B (functional layer), a laminate was produced in the same manner as in Example 4, except that the thickness was set to 3.0 μm.

[Comparative Example 3]

In forming the hard coat layer B (functional layer), a laminate was produced in the same manner as in Example 3, except that the thickness was set to 2.5 μm.

[Comparative Example 4]

In forming the hard coat layer B (functional layer), the following resin composition 9 for hard coat layer was used, and a laminate was produced in the same manner as in Example 3, except that the thickness was set to 2.5 μm.

(Composition of resin composition 9 for hard coat layer)

· Urethane acrylate (product name “8UX-141A”, manufactured by Taisei Fine Chemicals): 100 parts by mass (converted to 100% solid content)

· Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 4 parts by mass

· Antifouling agent (product name “DAC-HP”, manufactured by Daikin): 0.5 parts by mass (value converted to 100% solid content)

· Antistatic agent (product name “Beam Set MT-2”, manufactured by Arakawa Chemical Industry Co., Ltd.): 10 parts by mass (converted to 100% solid content)

· Methyl isobutyl ketone: 250 parts by mass

[Comparative Example 5]

A laminate was produced in the same manner as in Example 9, except that the thickness of the functional layer was 10.3 μm.

[evaluation]

(1) Charge amount after eraser test

The following eraser test was performed on the surface on the functional layer side of the laminates of Examples and Comparative Examples, and the amount of charge on the functional layer side surface of the laminate after the eraser test was measured.

First, an ionizer was applied to a glass plate as a test stand at 23 ± 5°C and 40 ± 10% RH for 1 minute to eliminate static electricity. Additionally, a laminate of 20 mm

Next, the end of the laminate was fixed on a glass plate with cellophane tape, and an eraser test was performed on the surface of the laminate on the functional layer side. Specifically, using an eraser with a diameter of 6 mm made by Minoan, insert it into a jig with a hole of 6 mm in diameter so that the tip of the eraser is exposed by 4 mm, and this jig with an eraser is run on a Gakjin type friction fastness tester (product name “AB-301”) , Tester (manufactured by Sangyo), the surface of the functional layer side of the laminate was erased with an eraser at a temperature of 23 ± 5°C and a humidity of 40 ± 10% RH, with a load of 9.8 N, a moving speed of 80 mm/sec, and a moving distance of 40 mm. 2500 rounds of rubbing.

Next, the laminate after the eraser test was set to a Faraday gauge, and the amount of electric charge was measured. At this time, the laminate after the eraser test was lifted using insulating and non-magnetic tweezers. In addition, after lifting the laminate after the eraser test, the amount of electric charge was measured without touching it to another fixed surface. As a Faraday gauge, a Faraday cage “KQ-1400” manufactured by Kasuga Denki Co., Ltd. was used. Additionally, as the ionizer, a fan-type ionizer “KD-750B” manufactured by Gasga Denki Co., Ltd. was used. Additionally, as tweezers, ESD (electrostatic protection) tweezers “P-643-S” manufactured by Kenneth Co. were used.

(2) Friction force before and after eraser test

The above-described eraser test was performed on the surface on the functional layer side of the laminates of Examples and Comparative Examples, and the frictional force against the eraser on the functional layer side surface of the laminate before and after the eraser test was measured.

In measuring the frictional force against an eraser, an eraser with a diameter of 6 mm made by Minoan is used and inserted into a jig with a hole of 6 mm in diameter so that the tip of the eraser is exposed by 4 mm, and this jig with an eraser is used in a continuous weighted scratch strength tester ( Product name “TRIBOGEAR TYPE18”, manufactured by Shinto Chemical Co., Ltd.), at a temperature of 23 ± 5°C and a humidity of 40 ± 10% RH, with a load of 1.96 N and a moving speed of 840 mm/min, the laminate was erased with an eraser. The surface on the functional layer side was rubbed in the order of the part where the eraser test was not performed, the part where the eraser test was performed, and the part where the eraser test was not performed, and the friction force was measured. At that time, as shown in FIG. 2, the eraser was moved perpendicularly to the longitudinal direction of the rectangular eraser test implementation section 32, as indicated by the arrow.

And, regarding the frictional force against the eraser in the eraser test implementation section, the maximum value of the frictional force was obtained. In addition, regarding the frictional force against the eraser in the section where the eraser test was not performed, as shown in FIG. 2, when the point at which the frictional force against the eraser of the eraser test section 32 is the maximum value is set to 0 mm, the area where the eraser test was not performed ( In 31), the average value of friction force in the range of 4.2 mm to 9.8 mm was obtained based on the above point (0 mm).

In addition, the ratio of the friction force before and after the eraser test is obtained by the following equation, assuming that the average value of the friction force in the area where the eraser test was not performed is A and the maximum value of the friction force in the eraser test performed section is B on the surface on the functional layer side of the above-described laminate. Calculated.

Ratio of friction force = B/A

(3) Slipperiness before and after eraser test

The above-described eraser test was performed on the surface on the functional layer side of the laminates of Examples and Comparative Examples, and the slipperiness of the functional layer side surface of the laminate before and after the eraser test was evaluated. Specifically, the surface on the functional layer side of the above-mentioned laminate with a fingertip is touched in the order of the eraser test not performed area, the eraser test performed area, and the eraser test not performed area at a temperature of 23 ± 5°C and a humidity of 40 ± 10% RH. It was rubbed at a moving speed of 10 cm/sec, and the slipperiness in the eraser test section at that time was evaluated based on the following criteria.

A: More than 7 out of 10 people did not feel stuck.

B: 5 or 6 out of 10 people did not feel stuck

C: 6 or 7 out of 10 people felt stuck

D: More than 8 out of 10 people felt stuck

(4) Steel wool test

First, a protective film having an adhesive layer on one side of the PET substrate was placed on the side of the laminate substrate layer with a size of 4 cm ㎛ or less), the ends of the laminate were fixed with cellophane tape to the test table of Gakjin-type friction fastness tester AB-301 manufactured by Tester Sangyo. Next, using #0000 steel wool (Bornstar #0000 manufactured by Nippon Steel Wool Co., Ltd.), the steel wool was fixed to a 2 cm : 9.8 N, reciprocating speed: 40 rpm, reciprocating distance: 40 mm, installation area of steel wool: 4 cm ² , the surface of the functional layer side of the display device laminate was rubbed 2500 reciprocations. Then, the presence or absence of scratches was confirmed through transmission and reflection.

[Table 1]

(5) Ratio of the number of atoms of fluorine to the total number of atoms of all elements before and after the eraser test

The eraser test described above was performed on the surface on the functional layer side of the laminate of Example 1 and Comparative Example 1, and the eraser and the functional layer side of the laminate before and after the eraser test were measured by X-ray photoelectron spectroscopy (XPS). The composition of the surface of the eraser before and after the test was analyzed. First, using an The X-ray photoelectron spectrum was measured using the target element.

From the obtained spectrum, the background determined by the Shirley method was subtracted, and the ratio of the number of atoms of each element (carbon atom, oxygen atom, fluorine) to the total number of atoms of all elements on the sample surface was calculated from the area of the peak using the relative sensitivity coefficient method. The atomic number ratio (at%) of each atom when the total number of atoms, nitrogen atom, silicon atom, calcium atom, and chlorine atom is 100 at%, was determined. The results are shown in Tables 2 and 3.

(Measuring conditions)

· Incident X-ray: Monochromated Al-Kα ray (monochromatized X-ray, Hv=1486.6eV)

· X-ray irradiation area (measurement area): 110㎛ϕ

· X-ray output: 150W (15kV·6.7mA)

· Photoelectron introduction angle: 90°±15° (sample normal is 0°)

· Charge neutralization conditions: electron neutralizing gun (+6V, 0.05mA), low-acceleration Ar ⁺ ion irradiation

· Measured peaks: C1s, O1s, F1s, N1s, Si2p, Ca2p, Cl2p

[Table 2]

[Table 3]

From Tables 2 to 3, after the eraser test, the ratio of the number of atoms of fluorine to the total number of atoms of all elements on the side of the functional layer side of the laminate decreases, and the ratio of the number of atoms of fluorine to the total number of atoms of all elements on the side of the eraser decreases. Since the ratio of the number of fluorine atoms increased, it was confirmed that the fluorine atoms contained in the functional layer adhered to the eraser by rubbing the surface on the functional layer side of the laminate with an eraser. This means that by rubbing the surface of the functional layer side of the laminate with an eraser, the surface of the functional layer becomes negatively charged, and as a result, the contact surface of the eraser becomes positively charged. As a result, the electrostatic force increases and the attractive force increases, resulting in negative sound. It is thought that strong fluorine detaches from the surface of the functional layer and adheres to the surface of the eraser.

Additionally, from Table 1, it was confirmed that when the absolute value of the charge on the functional layer side of the laminate after the eraser test was within a predetermined range, there was little change in slipperiness before and after the eraser test, and the wear resistance was excellent. This means that when the absolute value of the amount of charge on the surface of the functional layer side of the laminate after the eraser test is within a predetermined range, desorption of fluorine from the surface of the functional layer can be suppressed, and as a result, excellent wear resistance can be obtained. I think so.

That is, in this disclosure, the following invention can be provided.

[1] A laminate for a display device having a base layer and a functional layer containing fluorine, wherein a load of 9.8 N is applied to the surface of the display device laminate on the side of the functional layer using an eraser with a diameter of 6 mm to 2500 A laminate for a display device, wherein the absolute value of the amount of charge on the surface on the functional layer side of the laminate for a display device after performing a reciprocating rubbing eraser test is 10.0 nC or less.

[2] The ratio of the maximum value of the frictional force against the eraser after the eraser test to the average value of the initial frictional force against the eraser on the surface of the functional layer side of the laminate for the display device is 1.7 or less, [ The laminate for a display device according to [1].

[3] The ratio of the number of fluorine atoms to the total number of atoms of all elements on the surface on the functional layer side initially, as measured by X-ray photoelectron spectroscopy, the total surface on the functional layer side after the eraser test. The laminate for a display device according to [1] or [2], wherein the ratio of the number of fluorine atoms to the total number of atoms of the element is 0.4 or more.

[4] The laminate for a display device according to any one of [1] to [3], wherein the functional layer contains an antistatic agent.

[5] The laminate for a display device according to [4], wherein the antistatic agent is a conductive polymer.

[6] The laminate for a display device according to any one of [1] to [5], which has an impact absorption layer on the side of the base layer opposite to the functional layer or between the base layer and the functional layer.

[7] The laminate for a display device according to any one of [1] to [6], which has an adhesive layer for sticking on a side of the base layer opposite to the functional layer.

[8] The display device laminate according to any one of [1] to [7], wherein the distance between the outermost surface on the functional layer side of the display device laminate and the layer containing the antistatic agent is 10 μm or less.

[9] The laminate for a display device according to any one of [1] to [8], wherein an anti-reflection layer is disposed on the outermost surface of the laminate for a display device on the functional layer side.

[10] A display device comprising a display panel and the display device laminate according to any one of [1] to [9] disposed on an observer side of the display panel.

1: Laminate for display device
2: Base layer
3: Functional layer
4: Hard coat layer
5: Shock absorbing layer
6: Adhesive layer for sticking
7: Interlayer adhesive layer
20: Flexible display device
21: display panel

Claims (10)

A laminate for a display device having a base layer and a functional layer containing fluorine,
After performing an eraser test by applying a load of 9.8 N using an eraser with a diameter of 6 mm and rubbing the surface on the functional layer side of the display device laminate for 2500 reciprocations, on the functional layer side surface of the display device laminate A laminate for a display device whose absolute value of charge is 10.0 nC or less. According to paragraph 1,
A laminate for a display device, wherein the ratio of the maximum value of the frictional force against the eraser after the eraser test to the average value of the initial frictional force against the eraser on the surface of the functional layer side of the laminate for a display device at the initial stage is 1.7 or less. sifter. According to paragraph 1,
The total number of elements in the surface of the functional layer side after the eraser test relative to the ratio of the number of atoms of fluorine to the total number of atoms of all elements in the surface of the functional layer side initially, as measured by X-ray photoelectron spectroscopy. A laminate for a display device, wherein the ratio of the number of fluorine atoms to the number of atoms is 0.4 or more. According to paragraph 1,
A laminate for a display device, wherein the functional layer contains an antistatic agent. According to paragraph 4,
A laminate for a display device, wherein the antistatic agent is a conductive polymer. According to paragraph 1,
A laminate for a display device, which has an impact absorption layer on the side of the base layer opposite to the functional layer or between the base layer and the functional layer. According to paragraph 1,
A laminate for a display device, which has an adhesive layer for sticking on a side of the base layer opposite to the functional layer. According to paragraph 1,
A laminate for a display device, wherein the distance between the outermost surface on the functional layer side of the display device laminate and the layer containing an antistatic agent is 10 μm or less. According to paragraph 1,
A laminate for a display device, wherein an anti-reflection layer is disposed on the outermost surface of the laminate for a display device on the functional layer side. a display panel,
The laminate for a display device according to any one of claims 1 to 9, which is disposed on the observer side of the display panel.
Equipped with a display device.

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